Add compass-tasks

Registered tasks and MQ modules for Compass

Change-Id: Id1569a61fe53357d53448478d5ba42cb1f386bc6
Signed-off-by: Harry Huang <huangxiangyu5@huawei.com>

16 files changed, 9715 insertions, 0 deletions

diff --git a/compass-tasks/db/api/__init__.py b/compass-tasks/db/api/__init__.py
new file mode 100644
index 0000000..5e42ae9
--- /dev/null
+++ b/compass-tasks/db/api/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2014 Huawei Technologies Co. Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
diff --git a/compass-tasks/db/api/adapter.py b/compass-tasks/db/api/adapter.py
new file mode 100644
index 0000000..c3ad48d
--- /dev/null
+++ b/compass-tasks/db/api/adapter.py
@@ -0,0 +1,313 @@
+# Copyright 2014 Huawei Technologies Co. Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Adapter related database operations."""
+import logging
+import re
+
+from compass.db.api import database
+from compass.db.api import utils
+from compass.db import exception
+from compass.db import models
+
+from compass.utils import setting_wrapper as setting
+from compass.utils import util
+
+
+OSES = None
+OS_INSTALLERS = None
+PACKAGE_INSTALLERS = None
+ADAPTERS = None
+ADAPTERS_FLAVORS = None
+ADAPTERS_ROLES = None
+
+
+def _get_oses_from_configuration():
+    """Get all os configs from os configuration dir.
+
+    Example: {
+        <os_name>: {
+            'name': <os_name>,
+            'id': <os_name>,
+            'os_id': <os_name>,
+            'deployable': True
+        }
+    }
+    """
+    configs = util.load_configs(setting.OS_DIR)
+    systems = {}
+    for config in configs:
+        logging.info('get config %s', config)
+        system_name = config['NAME']
+        parent_name = config.get('PARENT', None)
+        system = {
+            'name': system_name,
+            'id': system_name,
+            'os_id': system_name,
+            'parent': parent_name,
+            'parent_id': parent_name,
+            'deployable': config.get('DEPLOYABLE', False)
+        }
+        systems[system_name] = system
+    parents = {}
+    for name, system in systems.items():
+        parent = system.get('parent', None)
+        parents[name] = parent
+    for name, system in systems.items():
+        util.recursive_merge_dict(name, systems, parents)
+    return systems
+
+
+def _get_installers_from_configuration(configs):
+    """Get installers from configurations.
+
+    Example: {
+        <installer_isntance>: {
+            'alias': <instance_name>,
+            'id': <instance_name>,
+            'name': <name>,
+            'settings': <dict pass to installer plugin>
+        }
+    }
+    """
+    installers = {}
+    for config in configs:
+        name = config['NAME']
+        instance_name = config.get('INSTANCE_NAME', name)
+        installers[instance_name] = {
+            'alias': instance_name,
+            'id': instance_name,
+            'name': name,
+            'settings': config.get('SETTINGS', {})
+        }
+    return installers
+
+
+def _get_os_installers_from_configuration():
+    """Get os installers from os installer config dir."""
+    configs = util.load_configs(setting.OS_INSTALLER_DIR)
+    return _get_installers_from_configuration(configs)
+
+
+def _get_package_installers_from_configuration():
+    """Get package installers from package installer config dir."""
+    configs = util.load_configs(setting.PACKAGE_INSTALLER_DIR)
+    return _get_installers_from_configuration(configs)
+
+
+def _get_adapters_from_configuration():
+    """Get adapters from adapter config dir."""
+    configs = util.load_configs(setting.ADAPTER_DIR)
+    adapters = {}
+    for config in configs:
+        logging.info('add config %s to adapter', config)
+        if 'OS_INSTALLER' in config:
+            os_installer = OS_INSTALLERS[config['OS_INSTALLER']]
+        else:
+            os_installer = None
+
+        if 'PACKAGE_INSTALLER' in config:
+            package_installer = PACKAGE_INSTALLERS[
+                config['PACKAGE_INSTALLER']
+            ]
+        else:
+            package_installer = None
+
+        adapter_name = config['NAME']
+        parent_name = config.get('PARENT', None)
+        adapter = {
+            'name': adapter_name,
+            'id': adapter_name,
+            'parent': parent_name,
+            'parent_id': parent_name,
+            'display_name': config.get('DISPLAY_NAME', adapter_name),
+            'os_installer': os_installer,
+            'package_installer': package_installer,
+            'deployable': config.get('DEPLOYABLE', False),
+            'health_check_cmd': config.get('HEALTH_CHECK_COMMAND', None),
+            'supported_oses': [],
+            'roles': [],
+            'flavors': []
+        }
+        supported_os_patterns = [
+            re.compile(supported_os_pattern)
+            for supported_os_pattern in config.get('SUPPORTED_OS_PATTERNS', [])
+        ]
+        for os_name, os in OSES.items():
+            if not os.get('deployable', False):
+                continue
+            for supported_os_pattern in supported_os_patterns:
+                if supported_os_pattern.match(os_name):
+                    adapter['supported_oses'].append(os)
+                    break
+        adapters[adapter_name] = adapter
+
+    parents = {}
+    for name, adapter in adapters.items():
+        parent = adapter.get('parent', None)
+        parents[name] = parent
+    for name, adapter in adapters.items():
+        util.recursive_merge_dict(name, adapters, parents)
+    return adapters
+
+
+def _add_roles_from_configuration():
+    """Get roles from roles config dir and update to adapters."""
+    configs = util.load_configs(setting.ADAPTER_ROLE_DIR)
+    for config in configs:
+        logging.info(
+            'add config %s to role', config
+        )
+        adapter_name = config['ADAPTER_NAME']
+        adapter = ADAPTERS[adapter_name]
+        adapter_roles = ADAPTERS_ROLES.setdefault(adapter_name, {})
+        for role_dict in config['ROLES']:
+            role_name = role_dict['role']
+            display_name = role_dict.get('display_name', role_name)
+            adapter_roles[role_name] = {
+                'name': role_name,
+                'id': '%s:%s' % (adapter_name, role_name),
+                'adapter_id': adapter_name,
+                'adapter_name': adapter_name,
+                'display_name': display_name,
+                'description': role_dict.get('description', display_name),
+                'optional': role_dict.get('optional', False)
+            }
+    parents = {}
+    for name, adapter in ADAPTERS.items():
+        parent = adapter.get('parent', None)
+        parents[name] = parent
+    for adapter_name, adapter_roles in ADAPTERS_ROLES.items():
+        util.recursive_merge_dict(adapter_name, ADAPTERS_ROLES, parents)
+    for adapter_name, adapter_roles in ADAPTERS_ROLES.items():
+        adapter = ADAPTERS[adapter_name]
+        adapter['roles'] = adapter_roles.values()
+
+
+def _add_flavors_from_configuration():
+    """Get flavors from flavor config dir and update to adapters."""
+    configs = util.load_configs(setting.ADAPTER_FLAVOR_DIR)
+    for config in configs:
+        logging.info('add config %s to flavor', config)
+        adapter_name = config['ADAPTER_NAME']
+        adapter = ADAPTERS[adapter_name]
+        adapter_flavors = ADAPTERS_FLAVORS.setdefault(adapter_name, {})
+        adapter_roles = ADAPTERS_ROLES[adapter_name]
+        for flavor_dict in config['FLAVORS']:
+            flavor_name = flavor_dict['flavor']
+            flavor_id = '%s:%s' % (adapter_name, flavor_name)
+            flavor = {
+                'name': flavor_name,
+                'id': flavor_id,
+                'adapter_id': adapter_name,
+                'adapter_name': adapter_name,
+                'display_name': flavor_dict.get('display_name', flavor_name),
+                'template': flavor_dict.get('template', None)
+            }
+            flavor_roles = flavor_dict.get('roles', [])
+            roles_in_flavor = []
+            for flavor_role in flavor_roles:
+                if isinstance(flavor_role, basestring):
+                    role_name = flavor_role
+                    role_in_flavor = {
+                        'name': role_name,
+                        'flavor_id': flavor_id
+                    }
+                else:
+                    role_in_flavor = flavor_role
+                    role_in_flavor['flavor_id'] = flavor_id
+                    if 'role' in role_in_flavor:
+                        role_in_flavor['name'] = role_in_flavor['role']
+                        del role_in_flavor['role']
+                    role_name = role_in_flavor['name']
+                role = adapter_roles[role_name]
+                util.merge_dict(role_in_flavor, role, override=False)
+                roles_in_flavor.append(role_in_flavor)
+            flavor['roles'] = roles_in_flavor
+            adapter_flavors[flavor_name] = flavor
+    parents = {}
+    for name, adapter in ADAPTERS.items():
+        parent = adapter.get('parent', None)
+        parents[name] = parent
+    for adapter_name, adapter_roles in ADAPTERS_FLAVORS.items():
+        util.recursive_merge_dict(adapter_name, ADAPTERS_FLAVORS, parents)
+    for adapter_name, adapter_flavors in ADAPTERS_FLAVORS.items():
+        adapter = ADAPTERS[adapter_name]
+        adapter['flavors'] = adapter_flavors.values()
+
+
+def load_adapters_internal(force_reload=False):
+    """Load adapter related configurations into memory.
+
+    If force_reload, reload all configurations even it is loaded already.
+    """
+    global OSES
+    if force_reload or OSES is None:
+        OSES = _get_oses_from_configuration()
+    global OS_INSTALLERS
+    if force_reload or OS_INSTALLERS is None:
+        OS_INSTALLERS = _get_os_installers_from_configuration()
+    global PACKAGE_INSTALLERS
+    if force_reload or PACKAGE_INSTALLERS is None:
+        PACKAGE_INSTALLERS = _get_package_installers_from_configuration()
+    global ADAPTERS
+    if force_reload or ADAPTERS is None:
+        ADAPTERS = _get_adapters_from_configuration()
+    global ADAPTERS_ROLES
+    if force_reload or ADAPTERS_ROLES is None:
+        ADAPTERS_ROLES = {}
+        _add_roles_from_configuration()
+    global ADAPTERS_FLAVORS
+    if force_reload or ADAPTERS_FLAVORS is None:
+        ADAPTERS_FLAVORS = {}
+        _add_flavors_from_configuration()
+
+
+def get_adapters_internal(force_reload=False):
+    """Get all deployable adapters."""
+    load_adapters_internal(force_reload=force_reload)
+    adapter_mapping = {}
+    for adapter_name, adapter in ADAPTERS.items():
+        if adapter.get('deployable'):
+            # TODO(xicheng): adapter should be filtered before
+            # return to caller.
+            adapter_mapping[adapter_name] = adapter
+        else:
+            logging.info(
+                'ignore adapter %s since it is not deployable',
+                adapter_name
+            )
+    return adapter_mapping
+
+
+def get_flavors_internal(force_reload=False):
+    """Get all deployable flavors."""
+    load_adapters_internal(force_reload=force_reload)
+    adapter_flavor_mapping = {}
+    for adapter_name, adapter_flavors in ADAPTERS_FLAVORS.items():
+        adapter = ADAPTERS.get(adapter_name, {})
+        for flavor_name, flavor in adapter_flavors.items():
+            if adapter.get('deployable'):
+                # TODO(xicheng): flavor dict should be filtered before
+                # return to caller.
+                adapter_flavor_mapping.setdefault(
+                    adapter_name, {}
+                )[flavor_name] = flavor
+            else:
+                logging.info(
+                    'ignore adapter %s since it is not deployable',
+                    adapter_name
+                )
+
+    return adapter_flavor_mapping
diff --git a/compass-tasks/db/api/adapter_holder.py b/compass-tasks/db/api/adapter_holder.py
new file mode 100644
index 0000000..91c65c4
--- /dev/null
+++ b/compass-tasks/db/api/adapter_holder.py
@@ -0,0 +1,155 @@
+# Copyright 2014 Huawei Technologies Co. Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Adapter related object holder."""
+import logging
+
+from compass.db.api import adapter as adapter_api
+from compass.db.api import database
+from compass.db.api import permission
+from compass.db.api import user as user_api
+from compass.db.api import utils
+from compass.db import exception
+
+
+SUPPORTED_FIELDS = [
+    'name',
+]
+RESP_FIELDS = [
+    'id', 'name', 'roles', 'flavors',
+    'os_installer', 'package_installer',
+    'supported_oses', 'display_name', 'health_check_cmd'
+]
+RESP_OS_FIELDS = [
+    'id', 'name', 'os_id'
+]
+RESP_ROLES_FIELDS = [
+    'id', 'name', 'display_name', 'description', 'optional'
+]
+RESP_FLAVORS_FIELDS = [
+    'id', 'adapter_id', 'adapter_name', 'name', 'display_name',
+    'template', 'roles'
+]
+
+
+ADAPTER_MAPPING = None
+FLAVOR_MAPPING = None
+
+
+def load_adapters(force_reload=False):
+    global ADAPTER_MAPPING
+    if force_reload or ADAPTER_MAPPING is None:
+        logging.info('load adapters into memory')
+        ADAPTER_MAPPING = adapter_api.get_adapters_internal(
+            force_reload=force_reload
+        )
+
+
+def load_flavors(force_reload=False):
+    global FLAVOR_MAPPING
+    if force_reload or FLAVOR_MAPPING is None:
+        logging.info('load flavors into memory')
+        FLAVOR_MAPPING = {}
+        adapters_flavors = adapter_api.get_flavors_internal(
+            force_reload=force_reload
+        )
+        for adapter_name, adapter_flavors in adapters_flavors.items():
+            for flavor_name, flavor in adapter_flavors.items():
+                FLAVOR_MAPPING['%s:%s' % (adapter_name, flavor_name)] = flavor
+
+
+def _filter_adapters(adapter_config, filter_name, filter_value):
+    if filter_name not in adapter_config:
+        return False
+    if isinstance(filter_value, list):
+        return bool(
+            adapter_config[filter_name] in filter_value
+        )
+    elif isinstance(filter_value, dict):
+        return all([
+            _filter_adapters(
+                adapter_config[filter_name],
+                sub_filter_key, sub_filter_value
+            )
+            for sub_filter_key, sub_filter_value in filter_value.items()
+        ])
+    else:
+        return adapter_config[filter_name] == filter_value
+
+
+@utils.supported_filters(optional_support_keys=SUPPORTED_FIELDS)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_ADAPTERS
+)
+@utils.output_filters(name=utils.general_filter_callback)
+@utils.wrap_to_dict(
+    RESP_FIELDS,
+    supported_oses=RESP_OS_FIELDS,
+    roles=RESP_ROLES_FIELDS,
+    flavors=RESP_FLAVORS_FIELDS
+)
+def list_adapters(user=None, session=None, **filters):
+    """list adapters."""
+    load_adapters()
+    return ADAPTER_MAPPING.values()
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_ADAPTERS
+)
+@utils.wrap_to_dict(
+    RESP_FIELDS,
+    supported_oses=RESP_OS_FIELDS,
+    roles=RESP_ROLES_FIELDS,
+    flavors=RESP_FLAVORS_FIELDS
+)
+def get_adapter(adapter_id, user=None, session=None, **kwargs):
+    """get adapter."""
+    load_adapters()
+    if adapter_id not in ADAPTER_MAPPING:
+        raise exception.RecordNotExists(
+            'adpater %s does not exist' % adapter_id
+        )
+    return ADAPTER_MAPPING[adapter_id]
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_METADATAS
+)
+@utils.wrap_to_dict(RESP_FLAVORS_FIELDS)
+def list_flavors(user=None, session=None, **filters):
+    """List flavors."""
+    load_flavors()
+    return FLAVOR_MAPPING.values()
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_METADATAS
+)
+@utils.wrap_to_dict(RESP_FLAVORS_FIELDS)
+def get_flavor(flavor_id, user=None, session=None, **kwargs):
+    """Get flavor."""
+    load_flavors()
+    if flavor_id not in FLAVOR_MAPPING:
+        raise exception.RecordNotExists(
+            'flavor %s does not exist' % flavor_id
+        )
+    return FLAVOR_MAPPING[flavor_id]
diff --git a/compass-tasks/db/api/cluster.py b/compass-tasks/db/api/cluster.py
new file mode 100644
index 0000000..7a7022c
--- /dev/null
+++ b/compass-tasks/db/api/cluster.py
@@ -0,0 +1,2444 @@
+# Copyright 2014 Huawei Technologies Co. Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Cluster database operations."""
+import copy
+import functools
+import logging
+import re
+
+from compass.db.api import adapter_holder as adapter_api
+from compass.db.api import database
+from compass.db.api import metadata_holder as metadata_api
+from compass.db.api import permission
+from compass.db.api import user as user_api
+from compass.db.api import utils
+from compass.db import exception
+from compass.db import models
+from compass.utils import util
+
+
+SUPPORTED_FIELDS = [
+    'name', 'os_name', 'owner',
+    'adapter_name', 'flavor_name'
+]
+SUPPORTED_CLUSTERHOST_FIELDS = []
+RESP_FIELDS = [
+    'id', 'name', 'os_name', 'os_id', 'adapter_id', 'flavor_id',
+    'reinstall_distributed_system', 'flavor',
+    'distributed_system_installed',
+    'owner', 'adapter_name', 'flavor_name',
+    'created_at', 'updated_at'
+]
+RESP_CLUSTERHOST_FIELDS = [
+    'id', 'host_id', 'clusterhost_id', 'machine_id',
+    'name', 'hostname', 'roles', 'os_installer',
+    'cluster_id', 'clustername', 'location', 'tag',
+    'networks', 'mac', 'switch_ip', 'port', 'switches',
+    'os_installed', 'distributed_system_installed',
+    'os_name', 'os_id', 'ip',
+    'reinstall_os', 'reinstall_distributed_system',
+    'owner', 'cluster_id',
+    'created_at', 'updated_at',
+    'patched_roles'
+]
+RESP_CONFIG_FIELDS = [
+    'os_config',
+    'package_config',
+    'config_step',
+    'config_validated',
+    'created_at',
+    'updated_at'
+]
+RESP_DEPLOYED_CONFIG_FIELDS = [
+    'deployed_os_config',
+    'deployed_package_config',
+    'created_at',
+    'updated_at'
+]
+RESP_METADATA_FIELDS = [
+    'os_config', 'package_config'
+]
+RESP_CLUSTERHOST_CONFIG_FIELDS = [
+    'package_config',
+    'os_config',
+    'config_step',
+    'config_validated',
+    'networks',
+    'created_at',
+    'updated_at'
+]
+RESP_CLUSTERHOST_DEPLOYED_CONFIG_FIELDS = [
+    'deployed_os_config',
+    'deployed_package_config',
+    'created_at',
+    'updated_at'
+]
+RESP_STATE_FIELDS = [
+    'id', 'state', 'percentage', 'message', 'severity',
+    'status', 'ready',
+    'created_at', 'updated_at'
+]
+RESP_CLUSTERHOST_STATE_FIELDS = [
+    'id', 'state', 'percentage', 'message', 'severity',
+    'ready', 'created_at', 'updated_at'
+]
+RESP_REVIEW_FIELDS = [
+    'cluster', 'hosts'
+]
+RESP_DEPLOY_FIELDS = [
+    'status', 'cluster', 'hosts'
+]
+IGNORE_FIELDS = ['id', 'created_at', 'updated_at']
+ADDED_FIELDS = ['name', 'adapter_id', 'os_id']
+OPTIONAL_ADDED_FIELDS = ['flavor_id']
+UPDATED_FIELDS = ['name', 'reinstall_distributed_system']
+ADDED_HOST_FIELDS = ['machine_id']
+UPDATED_HOST_FIELDS = ['name', 'reinstall_os']
+UPDATED_CLUSTERHOST_FIELDS = ['roles', 'patched_roles']
+PATCHED_CLUSTERHOST_FIELDS = ['patched_roles']
+UPDATED_CONFIG_FIELDS = [
+    'put_os_config', 'put_package_config', 'config_step'
+]
+UPDATED_DEPLOYED_CONFIG_FIELDS = [
+    'deployed_os_config', 'deployed_package_config'
+]
+PATCHED_CONFIG_FIELDS = [
+    'patched_os_config', 'patched_package_config', 'config_step'
+]
+UPDATED_CLUSTERHOST_CONFIG_FIELDS = [
+    'put_os_config',
+    'put_package_config'
+]
+PATCHED_CLUSTERHOST_CONFIG_FIELDS = [
+    'patched_os_config',
+    'patched_package_config'
+]
+UPDATED_CLUSTERHOST_DEPLOYED_CONFIG_FIELDS = [
+    'deployed_os_config',
+    'deployed_package_config'
+]
+UPDATED_CLUSTERHOST_STATE_FIELDS = [
+    'state', 'percentage', 'message', 'severity'
+]
+UPDATED_CLUSTERHOST_STATE_INTERNAL_FIELDS = [
+    'ready'
+]
+UPDATED_CLUSTER_STATE_FIELDS = ['state']
+IGNORE_UPDATED_CLUSTER_STATE_FIELDS = ['percentage', 'message', 'severity']
+UPDATED_CLUSTER_STATE_INTERNAL_FIELDS = ['ready']
+RESP_CLUSTERHOST_LOG_FIELDS = [
+    'clusterhost_id', 'id', 'host_id', 'cluster_id',
+    'filename', 'position', 'partial_line',
+    'percentage',
+    'message', 'severity', 'line_matcher_name'
+]
+ADDED_CLUSTERHOST_LOG_FIELDS = [
+    'filename'
+]
+UPDATED_CLUSTERHOST_LOG_FIELDS = [
+    'position', 'partial_line', 'percentage',
+    'message', 'severity', 'line_matcher_name'
+]
+
+
+@utils.supported_filters(optional_support_keys=SUPPORTED_FIELDS)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_CLUSTERS
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def list_clusters(user=None, session=None, **filters):
+    """List clusters."""
+    clusters = utils.list_db_objects(
+        session, models.Cluster, **filters
+    )
+    logging.info('user is %s', user.email)
+    if not user.is_admin and len(clusters):
+        clusters = [c for c in clusters if c.owner == user.email]
+    return clusters
+
+
+def _get_cluster(cluster_id, session=None, **kwargs):
+    """Get cluster by id."""
+    if isinstance(cluster_id, (int, long)):
+        return utils.get_db_object(
+            session, models.Cluster, id=cluster_id, **kwargs
+        )
+    raise exception.InvalidParameter(
+        'cluster id %s type is not int compatible' % cluster_id
+    )
+
+
+def get_cluster_internal(cluster_id, session=None, **kwargs):
+    """Helper function to get cluster.
+
+    Should be only used by other files under db/api.
+    """
+    return _get_cluster(cluster_id, session=session, **kwargs)
+
+
+def _get_cluster_host(
+    cluster_id, host_id, session=None, **kwargs
+):
+    """Get clusterhost by cluster id and host id."""
+    cluster = _get_cluster(cluster_id, session=session, **kwargs)
+    from compass.db.api import host as host_api
+    host = host_api.get_host_internal(host_id, session=session, **kwargs)
+    return utils.get_db_object(
+        session, models.ClusterHost,
+        cluster_id=cluster.id,
+        host_id=host.id,
+        **kwargs
+    )
+
+
+def _get_clusterhost(clusterhost_id, session=None, **kwargs):
+    """Get clusterhost by clusterhost id."""
+    if isinstance(clusterhost_id, (int, long)):
+        return utils.get_db_object(
+            session, models.ClusterHost,
+            clusterhost_id=clusterhost_id,
+            **kwargs
+        )
+    raise exception.InvalidParameter(
+        'clusterhost id %s type is not int compatible' % clusterhost_id
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_CLUSTERS
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def get_cluster(
+    cluster_id, exception_when_missing=True,
+    user=None, session=None, **kwargs
+):
+    """Get cluster info."""
+    return _get_cluster(
+        cluster_id,
+        session=session,
+        exception_when_missing=exception_when_missing
+    )
+
+
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_CLUSTERS)
+def is_cluster_os_ready(
+    cluster_id, exception_when_missing=True,
+    user=None, session=None, **kwargs
+):
+    cluster = utils.get_db_object(
+        session, models.Cluster, exception_when_missing, id=cluster_id)
+
+    all_states = ([i.host.state.ready for i in cluster.clusterhosts])
+
+    logging.info("is_cluster_os_ready: all_states %s" % all_states)
+
+    return all(all_states)
+
+
+def check_cluster_validated(cluster):
+    """Check cluster is validated."""
+    if not cluster.config_validated:
+        raise exception.Forbidden(
+            'cluster %s is not validated' % cluster.name
+        )
+
+
+def check_clusterhost_validated(clusterhost):
+    """Check clusterhost is validated."""
+    if not clusterhost.config_validated:
+        raise exception.Forbidden(
+            'clusterhost %s is not validated' % clusterhost.name
+        )
+
+
+def check_cluster_editable(
+    cluster, user=None,
+    check_in_installing=False
+):
+    """Check if cluster is editable.
+
+    If we try to set cluster
+    reinstall_distributed_system attribute or any
+    checking to make sure the cluster is not in installing state,
+    we can set check_in_installing to True.
+    Otherwise we will make sure the cluster is not in deploying or
+    deployed.
+    If user is not admin or not the owner of the cluster, the check
+    will fail to make sure he can not update the cluster attributes.
+    """
+    if check_in_installing:
+        if cluster.state.state == 'INSTALLING':
+            raise exception.Forbidden(
+                'cluster %s is not editable '
+                'when state is installing' % cluster.name
+            )
+#    elif (
+#        cluster.flavor_name and
+#        not cluster.reinstall_distributed_system
+#    ):
+#        raise exception.Forbidden(
+#            'cluster %s is not editable '
+#            'when not to be reinstalled' % cluster.name
+#        )
+    if user and not user.is_admin and cluster.creator_id != user.id:
+        raise exception.Forbidden(
+            'cluster %s is not editable '
+            'when user is not admin or cluster owner' % cluster.name
+        )
+
+
+def is_cluster_editable(
+    cluster, user=None,
+    check_in_installing=False
+):
+    """Get if cluster is editble."""
+    try:
+        check_cluster_editable(
+            cluster, user=user,
+            check_in_installing=check_in_installing
+        )
+        return True
+    except exception.Forbidden:
+        return False
+
+
+@utils.supported_filters(
+    ADDED_FIELDS,
+    optional_support_keys=OPTIONAL_ADDED_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(name=utils.check_name)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_CLUSTER
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def add_cluster(
+    exception_when_existing=True,
+    name=None, adapter_id=None, flavor_id=None,
+    user=None, session=None, **kwargs
+):
+    """Create a cluster."""
+    adapter = adapter_api.get_adapter(
+        adapter_id, user=user, session=session
+    )
+    # if flavor_id is not None, also set flavor field.
+    # In future maybe we can move the use of flavor from
+    # models.py to db/api and explictly get flavor when
+    # needed instead of setting flavor into cluster record.
+    flavor = {}
+    if flavor_id:
+        flavor = adapter_api.get_flavor(
+            flavor_id,
+            user=user, session=session
+        )
+        if flavor['adapter_id'] != adapter['id']:
+            raise exception.InvalidParameter(
+                'flavor %s is not of adapter %s' % (
+                    flavor_id, adapter_id
+                )
+            )
+
+    cluster = utils.add_db_object(
+        session, models.Cluster, exception_when_existing,
+        name, user.id, adapter_id=adapter_id,
+        flavor_id=flavor_id, flavor=flavor, **kwargs
+    )
+    return cluster
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(name=utils.check_name)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_CLUSTER
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def update_cluster(cluster_id, user=None, session=None, **kwargs):
+    """Update a cluster."""
+    cluster = _get_cluster(
+        cluster_id, session=session
+    )
+    check_cluster_editable(
+        cluster, user=user,
+        check_in_installing=(
+            kwargs.get('reinstall_distributed_system', False)
+        )
+    )
+    return utils.update_db_object(session, cluster, **kwargs)
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEL_CLUSTER
+)
+@utils.wrap_to_dict(
+    RESP_FIELDS + ['status', 'cluster', 'hosts'],
+    cluster=RESP_FIELDS,
+    hosts=RESP_CLUSTERHOST_FIELDS
+)
+def del_cluster(
+    cluster_id, force=False, from_database_only=False,
+    delete_underlying_host=False, user=None, session=None, **kwargs
+):
+    """Delete a cluster.
+
+    If force, the cluster will be deleted anyway. It is used by cli to
+    force clean a cluster in any case.
+    If from_database_only, the cluster recored will only be removed from
+    database. Otherwise, a del task is sent to celery to do clean deletion.
+    If delete_underlying_host, all hosts under this cluster will also be
+    deleted.
+    The backend will call del_cluster again with from_database_only set
+    when it has done the deletion work on os installer/package installer.
+    """
+    cluster = _get_cluster(
+        cluster_id, session=session
+    )
+    logging.debug(
+        'delete cluster %s with force=%s '
+        'from_database_only=%s delete_underlying_host=%s',
+        cluster.id, force, from_database_only, delete_underlying_host
+    )
+    # force set cluster state to ERROR and the state of any clusterhost
+    # in the cluster to ERROR when we want to delete the cluster anyway
+    # even the cluster is in installing or already installed.
+    # It let the api know the deleting is in doing when backend is doing
+    # the real deleting.
+    # In future we may import a new state like INDELETE to indicate
+    # the deleting is processing.
+    # We need discuss about if we can delete a cluster when it is already
+    # installed by api.
+    for clusterhost in cluster.clusterhosts:
+        if clusterhost.state.state != 'UNINITIALIZED' and force:
+            clusterhost.state.state = 'ERROR'
+        if delete_underlying_host:
+            host = clusterhost.host
+            if host.state.state != 'UNINITIALIZED' and force:
+                host.state.state = 'ERROR'
+    if cluster.state.state != 'UNINITIALIZED' and force:
+        cluster.state.state = 'ERROR'
+
+    check_cluster_editable(
+        cluster, user=user,
+        check_in_installing=True
+    )
+
+    # delete underlying host if delete_underlying_host is set.
+    if delete_underlying_host:
+        for clusterhost in cluster.clusterhosts:
+            # delete underlying host only user has permission.
+            from compass.db.api import host as host_api
+            host = clusterhost.host
+            if host_api.is_host_editable(
+                host, user=user, check_in_installing=True
+            ):
+                # Delete host record directly in database when there is no need
+                # to do the deletion in backend or from_database_only is set.
+                if host.state.state == 'UNINITIALIZED' or from_database_only:
+                    utils.del_db_object(
+                        session, host
+                    )
+
+    # Delete cluster record directly in database when there
+    # is no need to do the deletion in backend or from_database_only is set.
+    if cluster.state.state == 'UNINITIALIZED' or from_database_only:
+        return utils.del_db_object(
+            session, cluster
+        )
+    else:
+        from compass.tasks import client as celery_client
+        logging.info('send del cluster %s task to celery', cluster_id)
+        celery_client.celery.send_task(
+            'compass.tasks.delete_cluster',
+            (
+                user.email, cluster.id,
+                [
+                    clusterhost.host_id
+                    for clusterhost in cluster.clusterhosts
+                ],
+                delete_underlying_host
+            ),
+            queue=user.email,
+            exchange=user.email,
+            routing_key=user.email
+        )
+        return {
+            'status': 'delete action is sent',
+            'cluster': cluster,
+            'hosts': cluster.clusterhosts
+        }
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_CLUSTER_CONFIG
+)
+@utils.wrap_to_dict(RESP_CONFIG_FIELDS)
+def get_cluster_config(cluster_id, user=None, session=None, **kwargs):
+    """Get cluster config."""
+    return _get_cluster(cluster_id, session=session)
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_CLUSTER_CONFIG
+)
+@utils.wrap_to_dict(RESP_DEPLOYED_CONFIG_FIELDS)
+def get_cluster_deployed_config(cluster_id, user=None, session=None, **kwargs):
+    """Get cluster deployed config."""
+    return _get_cluster(cluster_id, session=session)
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_METADATAS
+)
+@utils.wrap_to_dict(RESP_METADATA_FIELDS)
+def get_cluster_metadata(cluster_id, user=None, session=None, **kwargs):
+    """Get cluster metadata.
+
+    If no flavor in the cluster, it means this is a os only cluster.
+    We ignore package metadata for os only cluster.
+    """
+    cluster = _get_cluster(cluster_id, session=session)
+    metadatas = {}
+    os_name = cluster.os_name
+    if os_name:
+        metadatas.update(
+            metadata_api.get_os_metadata(
+                os_name, session=session
+            )
+        )
+    flavor_id = cluster.flavor_id
+    if flavor_id:
+        metadatas.update(
+            metadata_api.get_flavor_metadata(
+                flavor_id,
+                user=user, session=session
+            )
+        )
+
+    return metadatas
+
+
+def _cluster_os_config_validates(
+    config, cluster, session=None, user=None, **kwargs
+):
+    """Check cluster os config validation."""
+    metadata_api.validate_os_config(
+        config, cluster.os_id
+    )
+
+
+def _cluster_package_config_validates(
+    config, cluster, session=None, user=None, **kwargs
+):
+    """Check cluster package config validation."""
+    metadata_api.validate_flavor_config(
+        config, cluster.flavor_id
+    )
+
+
+@utils.input_validates_with_args(
+    put_os_config=_cluster_os_config_validates,
+    put_package_config=_cluster_package_config_validates
+)
+@utils.output_validates_with_args(
+    os_config=_cluster_os_config_validates,
+    package_config=_cluster_package_config_validates
+)
+@utils.wrap_to_dict(RESP_CONFIG_FIELDS)
+def _update_cluster_config(cluster, session=None, user=None, **kwargs):
+    """Update a cluster config."""
+    check_cluster_editable(cluster, user=user)
+    return utils.update_db_object(
+        session, cluster, **kwargs
+    )
+
+
+# replace os_config to deployed_os_config,
+# package_config to deployed_package_config
+@utils.replace_filters(
+    os_config='deployed_os_config',
+    package_config='deployed_package_config'
+)
+@utils.supported_filters(
+    optional_support_keys=UPDATED_DEPLOYED_CONFIG_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_CLUSTER_CONFIG
+)
+@utils.wrap_to_dict(RESP_DEPLOYED_CONFIG_FIELDS)
+def update_cluster_deployed_config(
+    cluster_id, user=None, session=None, **kwargs
+):
+    """Update cluster deployed config."""
+    cluster = _get_cluster(cluster_id, session=session)
+    check_cluster_editable(cluster, user=user)
+    check_cluster_validated(cluster)
+    return utils.update_db_object(
+        session, cluster, **kwargs
+    )
+
+
+# replace os_config to put_os_config,
+# package_config to put_package_config in kwargs.
+# It tells db these fields will be updated not patched.
+@utils.replace_filters(
+    os_config='put_os_config',
+    package_config='put_package_config'
+)
+@utils.supported_filters(
+    optional_support_keys=UPDATED_CONFIG_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_CLUSTER_CONFIG
+)
+def update_cluster_config(cluster_id, user=None, session=None, **kwargs):
+    """Update cluster config."""
+    cluster = _get_cluster(cluster_id, session=session)
+    return _update_cluster_config(
+        cluster, session=session, user=user, **kwargs
+    )
+
+
+# replace os_config to patched_os_config and
+# package_config to patched_package_config in kwargs.
+# It tells db these fields will be patched not updated.
+@utils.replace_filters(
+    os_config='patched_os_config',
+    package_config='patched_package_config'
+)
+@utils.supported_filters(
+    optional_support_keys=PATCHED_CONFIG_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_CLUSTER_CONFIG
+)
+def patch_cluster_config(cluster_id, user=None, session=None, **kwargs):
+    """patch cluster config."""
+    cluster = _get_cluster(cluster_id, session=session)
+    return _update_cluster_config(
+        cluster, session=session, user=user, **kwargs
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEL_CLUSTER_CONFIG
+)
+@utils.wrap_to_dict(RESP_CONFIG_FIELDS)
+def del_cluster_config(cluster_id, user=None, session=None):
+    """Delete a cluster config."""
+    cluster = _get_cluster(
+        cluster_id, session=session
+    )
+    check_cluster_editable(cluster, user=user)
+    return utils.update_db_object(
+        session, cluster, os_config={},
+        package_config={}, config_validated=False
+    )
+
+
+def _roles_validates(roles, cluster, session=None, user=None):
+    """Check roles is validated to a cluster's roles."""
+    if roles:
+        if not cluster.flavor_name:
+            raise exception.InvalidParameter(
+                'not flavor in cluster %s' % cluster.name
+            )
+        cluster_roles = [role['name'] for role in cluster.flavor['roles']]
+        for role in roles:
+            if role not in cluster_roles:
+                raise exception.InvalidParameter(
+                    'role %s is not in cluster roles %s' % (
+                        role, cluster_roles
+                    )
+                )
+
+
+def _cluster_host_roles_validates(
+    value, cluster, host, session=None, user=None, **kwargs
+):
+    """Check clusterhost roles is validated by cluster and host."""
+    _roles_validates(value, cluster, session=session, user=user)
+
+
+def _clusterhost_roles_validates(
+    value, clusterhost, session=None, user=None, **kwargs
+):
+    """Check clusterhost roles is validated by clusterhost."""
+    _roles_validates(
+        value, clusterhost.cluster, session=session, user=user
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_HOST_FIELDS,
+    ignore_support_keys=UPDATED_CLUSTERHOST_FIELDS
+)
+@utils.input_validates(name=utils.check_name)
+def _add_host_if_not_exist(
+    machine_id, cluster, session=None, user=None, **kwargs
+):
+    """Add underlying host if it does not exist."""
+    from compass.db.api import host as host_api
+    host = host_api.get_host_internal(
+        machine_id, session=session, exception_when_missing=False
+    )
+    if host:
+        if kwargs:
+            # ignore update underlying host if host is not editable.
+            from compass.db.api import host as host_api
+            if host_api.is_host_editable(
+                host, user=cluster.creator,
+                check_in_installing=kwargs.get('reinstall_os', False),
+            ):
+                utils.update_db_object(
+                    session, host,
+                    **kwargs
+                )
+            else:
+                logging.debug(
+                    'ignore update host host %s '
+                    'since it is not editable' % host.name
+                )
+        else:
+            logging.debug('nothing to update for host %s', host.name)
+    else:
+        from compass.db.api import adapter_holder as adapter_api
+        adapter = adapter_api.get_adapter(
+            cluster.adapter_name, user=user, session=session
+        )
+        host = utils.add_db_object(
+            session, models.Host, False, machine_id,
+            os_name=cluster.os_name,
+            os_installer=adapter['os_installer'],
+            creator=cluster.creator,
+            **kwargs
+        )
+    return host
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_CLUSTERHOST_FIELDS,
+    ignore_support_keys=UPDATED_HOST_FIELDS
+)
+@utils.input_validates_with_args(
+    roles=_cluster_host_roles_validates
+)
+def _add_clusterhost_only(
+    cluster, host,
+    exception_when_existing=False,
+    session=None, user=None,
+    **kwargs
+):
+    """Get clusterhost only."""
+    if not cluster.state.state == "UNINITIALIZED":
+        cluster.state.ready = False
+        cluster.state.state = "UNINITIALIZED"
+        cluster.state.percentage = 0.0
+        utils.update_db_object(session, cluster.state, state="UNINITIALIZED")
+
+    return utils.add_db_object(
+        session, models.ClusterHost, exception_when_existing,
+        cluster.id, host.id, **kwargs
+    )
+
+
+@utils.supported_filters(
+    ADDED_HOST_FIELDS,
+    optional_support_keys=UPDATED_HOST_FIELDS + UPDATED_CLUSTERHOST_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+def _add_clusterhost(
+        cluster,
+        exception_when_existing=False,
+        session=None, user=None, machine_id=None, **kwargs
+):
+    """Add clusterhost and add underlying host if it does not exist."""
+    host = _add_host_if_not_exist(
+        machine_id, cluster, session=session,
+        user=user, **kwargs
+    )
+
+    return _add_clusterhost_only(
+        cluster, host, exception_when_existing=exception_when_existing,
+        session=session, user=user, **kwargs
+    )
+
+
+def _add_clusterhosts(cluster, machines, session=None, user=None):
+    """Add machines to cluster.
+
+    Args:
+       machines: list of dict which contains clusterost attr to update.
+
+    Examples:
+       [{'machine_id': 1, 'name': 'host1'}]
+    """
+    check_cluster_editable(
+        cluster, user=user,
+        check_in_installing=True
+    )
+    if cluster.state.state == 'SUCCESSFUL':
+        cluster.state.state == 'UPDATE_PREPARING'
+    for machine_dict in machines:
+        _add_clusterhost(
+            cluster, session=session, user=user, **machine_dict
+        )
+
+
+def _remove_clusterhosts(cluster, hosts, session=None, user=None):
+    """Remove hosts from cluster.
+
+    Args:
+       hosts: list of host id.
+    """
+    check_cluster_editable(
+        cluster, user=user,
+        check_in_installing=True
+    )
+    utils.del_db_objects(
+        session, models.ClusterHost,
+        cluster_id=cluster.id, host_id=hosts
+    )
+
+
+def _set_clusterhosts(cluster, machines, session=None, user=None):
+    """set machines to cluster.
+
+    Args:
+       machines: list of dict which contains clusterost attr to update.
+
+    Examples:
+       [{'machine_id': 1, 'name': 'host1'}]
+    """
+    check_cluster_editable(
+        cluster, user=user,
+        check_in_installing=True
+    )
+    utils.del_db_objects(
+        session, models.ClusterHost,
+        cluster_id=cluster.id
+    )
+    if cluster.state.state == 'SUCCESSFUL':
+        cluster.state.state = 'UPDATE_PREPARING'
+    for machine_dict in machines:
+        _add_clusterhost(
+            cluster, True, session=session, user=user, **machine_dict
+        )
+
+
+@utils.supported_filters(optional_support_keys=SUPPORTED_CLUSTERHOST_FIELDS)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_CLUSTERHOSTS
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_FIELDS)
+def list_cluster_hosts(cluster_id, user=None, session=None, **filters):
+    """List clusterhosts of a cluster."""
+    cluster = _get_cluster(cluster_id, session=session)
+    return utils.list_db_objects(
+        session, models.ClusterHost, cluster_id=cluster.id,
+        **filters
+    )
+
+
+@utils.supported_filters(optional_support_keys=SUPPORTED_CLUSTERHOST_FIELDS)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_CLUSTERHOSTS
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_FIELDS)
+def list_clusterhosts(user=None, session=None, **filters):
+    """List all clusterhosts."""
+    return utils.list_db_objects(
+        session, models.ClusterHost, **filters
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_CLUSTERHOSTS
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_FIELDS)
+def get_cluster_host(
+    cluster_id, host_id, exception_when_missing=True,
+    user=None, session=None, **kwargs
+):
+    """Get clusterhost info by cluster id and host id."""
+    return _get_cluster_host(
+        cluster_id, host_id, session=session,
+        exception_when_missing=exception_when_missing,
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_CLUSTERHOSTS
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_FIELDS)
+def get_clusterhost(
+    clusterhost_id, exception_when_missing=True,
+    user=None, session=None, **kwargs
+):
+    """Get clusterhost info by clusterhost id."""
+    return _get_clusterhost(
+        clusterhost_id, session=session,
+        exception_when_missing=exception_when_missing,
+        user=user
+    )
+
+
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_CLUSTER_HOSTS
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_FIELDS)
+def add_cluster_host(
+    cluster_id, exception_when_existing=True,
+    user=None, session=None, **kwargs
+):
+    """Add a host to a cluster."""
+    cluster = _get_cluster(cluster_id, session=session)
+    check_cluster_editable(
+        cluster, user=user,
+        check_in_installing=True
+    )
+    if cluster.state.state == 'SUCCESSFUL':
+        cluster.state.state = 'UPDATE_PREPARING'
+    return _add_clusterhost(
+        cluster, exception_when_existing,
+        session=session, user=user, **kwargs
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_HOST_FIELDS,
+    ignore_support_keys=(
+        UPDATED_CLUSTERHOST_FIELDS +
+        PATCHED_CLUSTERHOST_FIELDS
+    )
+)
+def _update_host_if_necessary(
+    clusterhost, session=None, user=None, **kwargs
+):
+    """Update underlying host if there is something to update."""
+    host = clusterhost.host
+    if kwargs:
+        # ignore update underlying host if the host is not editable.
+        from compass.db.api import host as host_api
+        if host_api.is_host_editable(
+            host, user=clusterhost.cluster.creator,
+            check_in_installing=kwargs.get('reinstall_os', False),
+        ):
+            utils.update_db_object(
+                session, host,
+                **kwargs
+            )
+        else:
+            logging.debug(
+                'ignore update host %s since it is not editable' % host.name
+            )
+    else:
+        logging.debug(
+            'nothing to update for host %s', host.name
+        )
+    return host
+
+
+@utils.supported_filters(
+    optional_support_keys=(
+        UPDATED_CLUSTERHOST_FIELDS +
+        PATCHED_CLUSTERHOST_FIELDS
+    ),
+    ignore_support_keys=UPDATED_HOST_FIELDS
+)
+@utils.input_validates_with_args(
+    roles=_clusterhost_roles_validates,
+    patched_roles=_clusterhost_roles_validates
+)
+def _update_clusterhost_only(
+    clusterhost, session=None, user=None, **kwargs
+):
+    """Update clusterhost only."""
+    check_cluster_editable(clusterhost.cluster, user=user)
+    return utils.update_db_object(
+        session, clusterhost, **kwargs
+    )
+
+
+@utils.wrap_to_dict(RESP_CLUSTERHOST_FIELDS)
+def _update_clusterhost(clusterhost, session=None, user=None, **kwargs):
+    """Update clusterhost and underlying host if necessary."""
+    _update_host_if_necessary(
+        clusterhost, session=session, user=user, **kwargs
+    )
+    return _update_clusterhost_only(
+        clusterhost, session=session, user=user, **kwargs
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=(UPDATED_HOST_FIELDS + UPDATED_CLUSTERHOST_FIELDS),
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_CLUSTER_HOSTS
+)
+def update_cluster_host(
+    cluster_id, host_id, user=None,
+    session=None, **kwargs
+):
+    """Update clusterhost by cluster id and host id."""
+    logging.info('updating kwargs: %s', kwargs)
+    clusterhost = _get_cluster_host(
+        cluster_id, host_id, session=session
+    )
+    return _update_clusterhost(
+        clusterhost, session=session, user=user, **kwargs
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=(UPDATED_HOST_FIELDS + UPDATED_CLUSTERHOST_FIELDS),
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_CLUSTER_HOSTS
+)
+def update_clusterhost(
+    clusterhost_id, user=None,
+    session=None, **kwargs
+):
+    """Update clusterhost by clusterhost id."""
+    clusterhost = _get_clusterhost(
+        clusterhost_id, session=session
+    )
+    return _update_clusterhost(
+        clusterhost, session=session, user=user, **kwargs
+    )
+
+
+# replace roles to patched_roles in kwargs.
+# It tells db roles field will be patched.
+@utils.replace_filters(
+    roles='patched_roles'
+)
+@utils.supported_filters(
+    optional_support_keys=PATCHED_CLUSTERHOST_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_CLUSTER_HOSTS
+)
+def patch_cluster_host(
+    cluster_id, host_id, user=None,
+    session=None, **kwargs
+):
+    """Patch clusterhost by cluster id and host id."""
+    logging.info("kwargs are %s", kwargs)
+    clusterhost = _get_cluster_host(
+        cluster_id, host_id, session=session
+    )
+    updated_clusterhost = _update_clusterhost(
+        clusterhost, session=session, user=user, **kwargs
+    )
+    return updated_clusterhost
+
+
+# replace roles to patched_roles in kwargs.
+# It tells db roles field will be patched.
+@utils.replace_filters(
+    roles='patched_roles'
+)
+@utils.supported_filters(
+    optional_support_keys=PATCHED_CLUSTERHOST_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_CLUSTER_HOSTS
+)
+def patch_clusterhost(
+    clusterhost_id, user=None, session=None,
+    **kwargs
+):
+    """Patch clusterhost by clusterhost id."""
+    clusterhost = _get_clusterhost(
+        clusterhost_id, session=session
+    )
+    return _update_clusterhost(
+        clusterhost, session=session, user=user, **kwargs
+    )
+
+
+@user_api.check_user_permission(
+    permission.PERMISSION_DEL_CLUSTER_HOST
+)
+@utils.wrap_to_dict(
+    RESP_CLUSTERHOST_FIELDS + ['status', 'host'],
+    host=RESP_CLUSTERHOST_FIELDS
+)
+def _del_cluster_host(
+    clusterhost,
+    force=False, from_database_only=False,
+    delete_underlying_host=False, user=None,
+    session=None, **kwargs
+):
+    """delete clusterhost.
+
+    If force, the cluster host will be deleted anyway.
+    If from_database_only, the cluster host recored will only be
+    deleted from database. Otherwise a celery task sent to do
+    clean deletion.
+    If delete_underlying_host, the underlying host will also be deleted.
+    The backend will call _del_cluster_host again when the clusterhost is
+    deleted from os installer/package installer with from_database_only
+    set.
+    """
+    # force set clusterhost state to ERROR when we want to delete the
+    # clusterhost anyway even the clusterhost is in installing or already
+    # installed. It let the api know the deleting is in doing when backend
+    # is doing the real deleting. In future we may import a new state like
+    # INDELETE to indicate the deleting is processing.
+    # We need discuss about if we can delete a clusterhost when it is already
+    # installed by api.
+    if clusterhost.state.state != 'UNINITIALIZED' and force:
+        clusterhost.state.state = 'ERROR'
+    if not force:
+        check_cluster_editable(
+            clusterhost.cluster, user=user,
+            check_in_installing=True
+        )
+    # delete underlying host if delete_underlying_host is set.
+    if delete_underlying_host:
+        host = clusterhost.host
+        if host.state.state != 'UNINITIALIZED' and force:
+            host.state.state = 'ERROR'
+        # only delete the host when user have the permission to delete it.
+        import compass.db.api.host as host_api
+        if host_api.is_host_editable(
+            host, user=user,
+            check_in_installing=True
+        ):
+            # if there is no need to do the deletion by backend or
+            # from_database_only is set, we only delete the record
+            # in database.
+            if host.state.state == 'UNINITIALIZED' or from_database_only:
+                utils.del_db_object(
+                    session, host
+                )
+
+    # if there is no need to do the deletion by backend or
+    # from_database_only is set, we only delete the record in database.
+    if clusterhost.state.state == 'UNINITIALIZED' or from_database_only:
+        return utils.del_db_object(
+            session, clusterhost
+        )
+    else:
+        logging.info(
+            'send del cluster %s host %s task to celery',
+            clusterhost.cluster_id, clusterhost.host_id
+        )
+        from compass.tasks import client as celery_client
+        celery_client.celery.send_task(
+            'compass.tasks.delete_cluster_host',
+            (
+                user.email, clusterhost.cluster_id, clusterhost.host_id,
+                delete_underlying_host
+            ),
+            queue=user.email,
+            exchange=user.email,
+            routing_key=user.email
+        )
+        return {
+            'status': 'delete action sent',
+            'host': clusterhost,
+        }
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+def del_cluster_host(
+    cluster_id, host_id,
+    force=False, from_database_only=False,
+    delete_underlying_host=False, user=None,
+    session=None, **kwargs
+):
+    """Delete clusterhost by cluster id and host id."""
+    clusterhost = _get_cluster_host(
+        cluster_id, host_id, session=session
+    )
+    return _del_cluster_host(
+        clusterhost, force=force, from_database_only=from_database_only,
+        delete_underlying_host=delete_underlying_host, user=user,
+        session=session, **kwargs
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+def del_clusterhost(
+    clusterhost_id,
+    force=False, from_database_only=False,
+    delete_underlying_host=False, user=None,
+    session=None, **kwargs
+):
+    """Delete clusterhost by clusterhost id."""
+    clusterhost = _get_clusterhost(
+        clusterhost_id, session=session
+    )
+    return _del_cluster_host(
+        clusterhost, force=force, from_database_only=from_database_only,
+        delete_underlying_host=delete_underlying_host, user=user,
+        session=session, **kwargs
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_CLUSTERHOST_CONFIG
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_CONFIG_FIELDS)
+def get_cluster_host_config(
+        cluster_id, host_id, user=None,
+        session=None, **kwargs
+):
+    """Get clusterhost config by cluster id and host id."""
+    return _get_cluster_host(
+        cluster_id, host_id, session=session
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_CLUSTERHOST_CONFIG
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_DEPLOYED_CONFIG_FIELDS)
+def get_cluster_host_deployed_config(
+    cluster_id, host_id, user=None, session=None, **kwargs
+):
+    """Get clusterhost deployed config by cluster id and host id."""
+    return _get_cluster_host(
+        cluster_id, host_id, session=session
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_CLUSTERHOST_CONFIG
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_CONFIG_FIELDS)
+def get_clusterhost_config(clusterhost_id, user=None, session=None, **kwargs):
+    """Get clusterhost config by clusterhost id."""
+    return _get_clusterhost(
+        clusterhost_id, session=session
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_CLUSTERHOST_CONFIG
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_DEPLOYED_CONFIG_FIELDS)
+def get_clusterhost_deployed_config(
+    clusterhost_id, user=None,
+    session=None, **kwargs
+):
+    """Get clusterhost deployed config by clusterhost id."""
+    return _get_clusterhost(
+        clusterhost_id, session=session
+    )
+
+
+def _clusterhost_os_config_validates(
+    config, clusterhost, session=None, user=None, **kwargs
+):
+    """Validate clusterhost's underlying host os config."""
+    from compass.db.api import host as host_api
+    host = clusterhost.host
+    host_api.check_host_editable(host, user=user)
+    metadata_api.validate_os_config(
+        config, host.os_id
+    )
+
+
+def _clusterhost_package_config_validates(
+    config, clusterhost, session=None, user=None, **kwargs
+):
+    """Validate clusterhost's cluster package config."""
+    cluster = clusterhost.cluster
+    check_cluster_editable(cluster, user=user)
+    metadata_api.validate_flavor_config(
+        config, cluster.flavor_id
+    )
+
+
+def _filter_clusterhost_host_editable(
+    config, clusterhost, session=None, user=None, **kwargs
+):
+    """Filter fields if the underlying host is not editable."""
+    from compass.db.api import host as host_api
+    host = clusterhost.host
+    return host_api.is_host_editable(host, user=user)
+
+
+@utils.input_filters(
+    put_os_config=_filter_clusterhost_host_editable,
+    patched_os_config=_filter_clusterhost_host_editable
+)
+@utils.input_validates_with_args(
+    put_os_config=_clusterhost_os_config_validates,
+    put_package_config=_clusterhost_package_config_validates
+)
+@utils.output_validates_with_args(
+    os_config=_clusterhost_os_config_validates,
+    package_config=_clusterhost_package_config_validates
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_CONFIG_FIELDS)
+def _update_clusterhost_config(clusterhost, session=None, user=None, **kwargs):
+    """Update clusterhost config."""
+    return utils.update_db_object(
+        session, clusterhost, **kwargs
+    )
+
+
+def _clusterhost_host_validated(
+    config, clusterhost, session=None, user=None, **kwargs
+):
+    """Check clusterhost's underlying host is validated."""
+    from compass.db.api import host as host_api
+    host = clusterhost.host
+    host_api.check_host_editable(host, user=user)
+    host_api.check_host_validated(host)
+
+
+def _clusterhost_cluster_validated(
+    config, clusterhost, session=None, user=None, **kwargs
+):
+    """Check clusterhost's cluster is validated."""
+    cluster = clusterhost.cluster
+    check_cluster_editable(cluster, user=user)
+    check_clusterhost_validated(clusterhost)
+
+
+@utils.input_filters(
+    deployed_os_config=_filter_clusterhost_host_editable,
+)
+@utils.input_validates_with_args(
+    deployed_os_config=_clusterhost_host_validated,
+    deployed_package_config=_clusterhost_cluster_validated
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_DEPLOYED_CONFIG_FIELDS)
+def _update_clusterhost_deployed_config(
+    clusterhost, session=None, user=None, **kwargs
+):
+    """Update clusterhost deployed config."""
+    return utils.update_db_object(
+        session, clusterhost, **kwargs
+    )
+
+
+# replace os_config to put_os_config and
+# package_config to put_package_config in kwargs.
+# It tells db these fields will be updated not patched.
+@utils.replace_filters(
+    os_config='put_os_config',
+    package_config='put_package_config'
+)
+@utils.supported_filters(
+    optional_support_keys=UPDATED_CLUSTERHOST_CONFIG_FIELDS,
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_CLUSTERHOST_CONFIG
+)
+def update_cluster_host_config(
+    cluster_id, host_id, user=None, session=None, **kwargs
+):
+    """Update clusterhost config by cluster id and host id."""
+    clusterhost = _get_cluster_host(
+        cluster_id, host_id, session=session
+    )
+    return _update_clusterhost_config(
+        clusterhost, user=user, session=session, **kwargs
+    )
+
+
+# replace os_config to deployed_os_config and
+# package_config to deployed_package_config in kwargs.
+@utils.replace_filters(
+    os_config='deployed_os_config',
+    package_config='deployed_package_config'
+)
+@utils.supported_filters(
+    optional_support_keys=UPDATED_CLUSTERHOST_DEPLOYED_CONFIG_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_CLUSTERHOST_CONFIG
+)
+def update_cluster_host_deployed_config(
+    cluster_id, host_id, user=None, session=None, **kwargs
+):
+    """Update clusterhost deployed config by cluster id and host id."""
+    clusterhost = _get_cluster_host(
+        cluster_id, host_id, session=session
+    )
+    return _update_clusterhost_deployed_config(
+        clusterhost, session=session, user=user, **kwargs
+    )
+
+
+# replace os_config to put_os_config and
+# package_config to put_package_config in kwargs.
+# It tells db these fields will be updated not patched.
+@utils.replace_filters(
+    os_config='put_os_config',
+    package_config='put_package_config'
+)
+@utils.supported_filters(
+    optional_support_keys=UPDATED_CLUSTERHOST_CONFIG_FIELDS,
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_CLUSTERHOST_CONFIG
+)
+def update_clusterhost_config(
+    clusterhost_id, user=None, session=None, **kwargs
+):
+    """Update clusterhost config by clusterhost id."""
+    clusterhost = _get_clusterhost(
+        clusterhost_id, session=session
+    )
+    return _update_clusterhost_config(
+        clusterhost, session=session, user=user, **kwargs
+    )
+
+
+# replace os_config to deployed_os_config and
+# package_config to deployed_package_config in kwargs.
+@utils.replace_filters(
+    os_config='deployed_os_config',
+    package_config='deployed_package_config'
+)
+@utils.supported_filters(
+    optional_support_keys=UPDATED_CLUSTERHOST_DEPLOYED_CONFIG_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_CLUSTERHOST_CONFIG
+)
+def update_clusterhost_deployed_config(
+    clusterhost_id, user=None, session=None, **kwargs
+):
+    """Update clusterhost deployed config by clusterhost id."""
+    clusterhost = _get_clusterhost(
+        clusterhost_id, session=session
+    )
+    return _update_clusterhost_deployed_config(
+        clusterhost, session=session, user=user, **kwargs
+    )
+
+
+# replace os_config to patched_os_config and
+# package_config to patched_package_config in kwargs
+# It tells db these fields will be patched not updated.
+@utils.replace_filters(
+    os_config='patched_os_config',
+    package_config='patched_package_config'
+)
+@utils.supported_filters(
+    optional_support_keys=PATCHED_CLUSTERHOST_CONFIG_FIELDS,
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_CLUSTERHOST_CONFIG
+)
+def patch_cluster_host_config(
+    cluster_id, host_id, user=None, session=None, **kwargs
+):
+    """patch clusterhost config by cluster id and host id."""
+    clusterhost = _get_cluster_host(
+        cluster_id, host_id, session=session
+    )
+    return _update_clusterhost_config(
+        clusterhost, session=session, user=user, **kwargs
+    )
+
+
+# replace os_config to patched_os_config and
+# package_config to patched_package_config in kwargs
+# It tells db these fields will be patched not updated.
+@utils.replace_filters(
+    os_config='patched_os_config',
+    package_config='patched_package_config'
+)
+@utils.supported_filters(
+    optional_support_keys=PATCHED_CLUSTERHOST_CONFIG_FIELDS,
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_CLUSTERHOST_CONFIG
+)
+def patch_clusterhost_config(
+    clusterhost_id, user=None, session=None, **kwargs
+):
+    """patch clusterhost config by clusterhost id."""
+    clusterhost = _get_clusterhost(
+        clusterhost_id, session=session
+    )
+    return _update_clusterhost_config(
+        clusterhost, session=session, user=user, **kwargs
+    )
+
+
+def _clusterhost_host_editable(
+    config, clusterhost, session=None, user=None, **kwargs
+):
+    """Check clusterhost underlying host is editable."""
+    from compass.db.api import host as host_api
+    host_api.check_host_editable(clusterhost.host, user=user)
+
+
+def _clusterhost_cluster_editable(
+    config, clusterhost, session=None, user=None, **kwargs
+):
+    """Check clusterhost's cluster is editable."""
+    check_cluster_editable(clusterhost.cluster, user=user)
+
+
+@utils.supported_filters(
+    optional_support_keys=['os_config', 'package_config']
+)
+@utils.input_filters(
+    os_config=_filter_clusterhost_host_editable,
+)
+@utils.output_validates_with_args(
+    package_config=_clusterhost_cluster_editable
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_CONFIG_FIELDS)
+def _delete_clusterhost_config(
+    clusterhost, session=None, user=None, **kwargs
+):
+    """delete clusterhost config."""
+    return utils.update_db_object(
+        session, clusterhost, config_validated=False,
+        **kwargs
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEL_CLUSTERHOST_CONFIG
+)
+def delete_cluster_host_config(
+    cluster_id, host_id, user=None, session=None
+):
+    """Delete a clusterhost config by cluster id and host id."""
+    clusterhost = _get_cluster_host(
+        cluster_id, host_id, session=session
+    )
+    return _delete_clusterhost_config(
+        clusterhost, session=session, user=user,
+        os_config={}, package_config={}
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEL_CLUSTERHOST_CONFIG
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_CONFIG_FIELDS)
+def delete_clusterhost_config(clusterhost_id, user=None, session=None):
+    """Delet a clusterhost config by clusterhost id."""
+    clusterhost = _get_clusterhost(
+        clusterhost_id, session=session
+    )
+    return _delete_clusterhost_config(
+        clusterhost, session=session, user=user,
+        os_config={}, package_config={}
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=['add_hosts', 'remove_hosts', 'set_hosts']
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_CLUSTER_HOSTS
+)
+@utils.wrap_to_dict(
+    ['hosts'],
+    hosts=RESP_CLUSTERHOST_FIELDS
+)
+def update_cluster_hosts(
+    cluster_id, add_hosts={}, set_hosts=None,
+    remove_hosts={}, user=None, session=None
+):
+    """Update cluster hosts."""
+    cluster = _get_cluster(cluster_id, session=session)
+    if remove_hosts:
+        _remove_clusterhosts(
+            cluster, session=session, user=user, **remove_hosts
+        )
+    if add_hosts:
+        _add_clusterhosts(
+            cluster, session=session, user=user, **add_hosts
+        )
+    if set_hosts is not None:
+        _set_clusterhosts(
+            cluster, session=session, user=user, **set_hosts
+        )
+
+    return {
+        'hosts': list_cluster_hosts(cluster_id, session=session)
+    }
+
+
+def validate_clusterhost(clusterhost, session=None):
+    """validate clusterhost."""
+    roles = clusterhost.roles
+    if not roles:
+        if clusterhost.cluster.flavor_name:
+            raise exception.InvalidParameter(
+                'empty roles for clusterhost %s' % clusterhost.name
+            )
+
+
+def validate_cluster(cluster, session=None):
+    """Validate cluster."""
+    if not cluster.clusterhosts:
+        raise exception.InvalidParameter(
+            'cluster %s does not have any hosts' % cluster.name
+        )
+    if cluster.flavor_name:
+        cluster_roles = cluster.flavor['roles']
+    else:
+        cluster_roles = []
+    necessary_roles = set([
+        role['name'] for role in cluster_roles if not role.get('optional')
+    ])
+    clusterhost_roles = set([])
+    interface_subnets = {}
+    for clusterhost in cluster.clusterhosts:
+        roles = clusterhost.roles
+        for role in roles:
+            clusterhost_roles.add(role['name'])
+        host = clusterhost.host
+        for host_network in host.host_networks:
+            interface_subnets.setdefault(
+                host_network.interface, set([])
+            ).add(host_network.subnet.subnet)
+    missing_roles = necessary_roles - clusterhost_roles
+    if missing_roles:
+        raise exception.InvalidParameter(
+            'cluster %s have some roles %s not assigned to any host' % (
+                cluster.name, list(missing_roles)
+            )
+        )
+    for interface, subnets in interface_subnets.items():
+        if len(subnets) > 1:
+            raise exception.InvalidParameter(
+                'cluster %s multi subnets %s in interface %s' % (
+                    cluster.name, list(subnets), interface
+                )
+            )
+
+
+@utils.supported_filters(optional_support_keys=['review'])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_REVIEW_CLUSTER
+)
+@utils.wrap_to_dict(
+    RESP_REVIEW_FIELDS,
+    cluster=RESP_CONFIG_FIELDS,
+    hosts=RESP_CLUSTERHOST_CONFIG_FIELDS
+)
+def review_cluster(cluster_id, review={}, user=None, session=None, **kwargs):
+    """review cluster.
+
+    Args:
+       cluster_id: the cluster id.
+       review: dict contains hosts to be reviewed. either contains key
+               hosts or clusterhosts. where hosts is a list of host id,
+               clusterhosts is a list of clusterhost id.
+    """
+    from compass.db.api import host as host_api
+    cluster = _get_cluster(cluster_id, session=session)
+    check_cluster_editable(cluster, user=user)
+    host_ids = review.get('hosts', [])
+    clusterhost_ids = review.get('clusterhosts', [])
+    clusterhosts = []
+    # Get clusterhosts need to be reviewed.
+    for clusterhost in cluster.clusterhosts:
+        if (
+            clusterhost.clusterhost_id in clusterhost_ids or
+            clusterhost.host_id in host_ids
+        ):
+            clusterhosts.append(clusterhost)
+
+    os_config = copy.deepcopy(cluster.os_config)
+    os_config = metadata_api.autofill_os_config(
+        os_config, cluster.os_id, cluster=cluster
+    )
+    metadata_api.validate_os_config(
+        os_config, cluster.os_id, True
+    )
+    for clusterhost in clusterhosts:
+        host = clusterhost.host
+        # ignore underlying host os config validation
+        # since the host is not editable
+        if not host_api.is_host_editable(
+            host, user=user, check_in_installing=False
+        ):
+            logging.info(
+                'ignore update host %s config '
+                'since it is not editable' % host.name
+            )
+            continue
+        host_os_config = copy.deepcopy(host.os_config)
+        host_os_config = metadata_api.autofill_os_config(
+            host_os_config, host.os_id,
+            host=host
+        )
+        deployed_os_config = util.merge_dict(
+            os_config, host_os_config
+        )
+        metadata_api.validate_os_config(
+            deployed_os_config, host.os_id, True
+        )
+        host_api.validate_host(host)
+        utils.update_db_object(
+            session, host, os_config=host_os_config, config_validated=True
+        )
+
+    package_config = copy.deepcopy(cluster.package_config)
+    if cluster.flavor_name:
+        package_config = metadata_api.autofill_flavor_config(
+            package_config, cluster.flavor_id,
+            cluster=cluster
+        )
+        metadata_api.validate_flavor_config(
+            package_config, cluster.flavor_id, True
+        )
+        for clusterhost in clusterhosts:
+            clusterhost_package_config = copy.deepcopy(
+                clusterhost.package_config
+            )
+            clusterhost_package_config = (
+                metadata_api.autofill_flavor_config(
+                    clusterhost_package_config,
+                    cluster.flavor_id,
+                    clusterhost=clusterhost
+                )
+            )
+            deployed_package_config = util.merge_dict(
+                package_config, clusterhost_package_config
+            )
+            metadata_api.validate_flavor_config(
+                deployed_package_config,
+                cluster.flavor_id, True
+            )
+            validate_clusterhost(clusterhost, session=session)
+            utils.update_db_object(
+                session, clusterhost,
+                package_config=clusterhost_package_config,
+                config_validated=True
+            )
+
+    validate_cluster(cluster, session=session)
+    utils.update_db_object(
+        session, cluster, os_config=os_config, package_config=package_config,
+        config_validated=True
+    )
+    return {
+        'cluster': cluster,
+        'hosts': clusterhosts
+    }
+
+
+@utils.supported_filters(optional_support_keys=['deploy'])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEPLOY_CLUSTER
+)
+@utils.wrap_to_dict(
+    RESP_DEPLOY_FIELDS,
+    cluster=RESP_CONFIG_FIELDS,
+    hosts=RESP_CLUSTERHOST_FIELDS
+)
+def deploy_cluster(
+    cluster_id, deploy={}, user=None, session=None, **kwargs
+):
+    """deploy cluster.
+
+    Args:
+       cluster_id: cluster id.
+       deploy: dict contains key either hosts or clusterhosts.
+               deploy['hosts'] is a list of host id,
+               deploy['clusterhosts'] is a list of clusterhost id.
+    """
+    from compass.db.api import host as host_api
+    from compass.tasks import client as celery_client
+    cluster = _get_cluster(cluster_id, session=session)
+    host_ids = deploy.get('hosts', [])
+    clusterhost_ids = deploy.get('clusterhosts', [])
+    clusterhosts = []
+    # get clusterhost to deploy.
+    for clusterhost in cluster.clusterhosts:
+        if (
+            clusterhost.clusterhost_id in clusterhost_ids or
+            clusterhost.host_id in host_ids
+        ):
+            clusterhosts.append(clusterhost)
+    check_cluster_editable(cluster, user=user)
+    check_cluster_validated(cluster)
+    utils.update_db_object(session, cluster.state, state='INITIALIZED')
+    for clusterhost in clusterhosts:
+        host = clusterhost.host
+        # ignore checking if underlying host is validated if
+        # the host is not editable.
+        if host_api.is_host_editable(host, user=user):
+            host_api.check_host_validated(host)
+            utils.update_db_object(session, host.state, state='INITIALIZED')
+        if cluster.flavor_name:
+            check_clusterhost_validated(clusterhost)
+            utils.update_db_object(
+                session, clusterhost.state, state='INITIALIZED'
+            )
+
+    celery_client.celery.send_task(
+        'compass.tasks.deploy_cluster',
+        (
+            user.email, cluster_id,
+            [clusterhost.host_id for clusterhost in clusterhosts]
+        ),
+        queue=user.email,
+        exchange=user.email,
+        routing_key=user.email
+    )
+    return {
+        'status': 'deploy action sent',
+        'cluster': cluster,
+        'hosts': clusterhosts
+    }
+
+
+@utils.supported_filters(optional_support_keys=['redeploy'])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEPLOY_CLUSTER
+)
+@utils.wrap_to_dict(
+    RESP_DEPLOY_FIELDS,
+    cluster=RESP_CONFIG_FIELDS,
+    hosts=RESP_CLUSTERHOST_FIELDS
+)
+def redeploy_cluster(
+    cluster_id, deploy={}, user=None, session=None, **kwargs
+):
+    """redeploy cluster.
+
+    Args:
+       cluster_id: cluster id.
+    """
+    from compass.db.api import host as host_api
+    from compass.tasks import client as celery_client
+    cluster = _get_cluster(cluster_id, session=session)
+
+    check_cluster_editable(cluster, user=user)
+    check_cluster_validated(cluster)
+    utils.update_db_object(
+        session, cluster.state,
+        state='INITIALIZED',
+        percentage=0,
+        ready=False
+    )
+    for clusterhost in cluster.clusterhosts:
+        host = clusterhost.host
+        # ignore checking if underlying host is validated if
+        # the host is not editable.
+        host_api.check_host_validated(host)
+        utils.update_db_object(
+            session, host.state,
+            state='INITIALIZED',
+            percentage=0,
+            ready=False
+        )
+        if cluster.flavor_name:
+            check_clusterhost_validated(clusterhost)
+            utils.update_db_object(
+                session,
+                clusterhost.state,
+                state='INITIALIZED',
+                percentage=0,
+                ready=False
+            )
+
+    celery_client.celery.send_task(
+        'compass.tasks.redeploy_cluster',
+        (
+            user.email, cluster_id
+        ),
+        queue=user.email,
+        exchange=user.email,
+        routing_key=user.email
+    )
+    return {
+        'status': 'redeploy action sent',
+        'cluster': cluster
+    }
+
+
+@utils.supported_filters(optional_support_keys=['apply_patch'])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEPLOY_CLUSTER
+)
+@utils.wrap_to_dict(
+    RESP_DEPLOY_FIELDS,
+    cluster=RESP_CONFIG_FIELDS,
+    hosts=RESP_CLUSTERHOST_FIELDS
+)
+def patch_cluster(cluster_id, user=None, session=None, **kwargs):
+
+    from compass.tasks import client as celery_client
+
+    cluster = _get_cluster(cluster_id, session=session)
+    celery_client.celery.send_task(
+        'compass.tasks.patch_cluster',
+        (
+            user.email, cluster_id,
+        ),
+        queue=user.email,
+        exchange=user.email,
+        routing_key=user.email
+    )
+    return {
+        'status': 'patch action sent',
+        'cluster': cluster
+    }
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_GET_CLUSTER_STATE
+)
+@utils.wrap_to_dict(RESP_STATE_FIELDS)
+def get_cluster_state(cluster_id, user=None, session=None, **kwargs):
+    """Get cluster state info."""
+    return _get_cluster(cluster_id, session=session).state_dict()
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_GET_CLUSTERHOST_STATE
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_STATE_FIELDS)
+def get_cluster_host_state(
+    cluster_id, host_id, user=None, session=None, **kwargs
+):
+    """Get clusterhost state merged with underlying host state."""
+    return _get_cluster_host(
+        cluster_id, host_id, session=session
+    ).state_dict()
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_GET_CLUSTERHOST_STATE
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_STATE_FIELDS)
+def get_cluster_host_self_state(
+    cluster_id, host_id, user=None, session=None, **kwargs
+):
+    """Get clusterhost itself state."""
+    return _get_cluster_host(
+        cluster_id, host_id, session=session
+    ).state
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_GET_CLUSTERHOST_STATE
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_STATE_FIELDS)
+def get_clusterhost_state(
+    clusterhost_id, user=None, session=None, **kwargs
+):
+    """Get clusterhost state merged with underlying host state."""
+    return _get_clusterhost(
+        clusterhost_id, session=session
+    ).state_dict()
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_GET_CLUSTERHOST_STATE
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_STATE_FIELDS)
+def get_clusterhost_self_state(
+    clusterhost_id, user=None, session=None, **kwargs
+):
+    """Get clusterhost itself state."""
+    return _get_clusterhost(
+        clusterhost_id, session=session
+    ).state
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_CLUSTERHOST_STATE_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_CLUSTERHOST_STATE
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_STATE_FIELDS)
+def update_cluster_host_state(
+    cluster_id, host_id, user=None, session=None, **kwargs
+):
+    """Update a clusterhost itself state."""
+    clusterhost = _get_cluster_host(
+        cluster_id, host_id, session=session
+    )
+    # Modify(harry): without progress_update.py to update cluster state
+    # update cluster state here
+    cluster = _get_cluster(clusterhost.cluster_id, session=session)
+    utils.update_db_object(session, clusterhost.state, **kwargs)
+    utils.update_db_object(session, cluster.state, **kwargs)
+    return clusterhost.state_dict()
+
+
+def _update_clusterhost_state(
+    clusterhost, from_database_only=False,
+    session=None, user=None, **kwargs
+):
+    """Update clusterhost state.
+
+    If from_database_only, the state will only be updated in database.
+    Otherwise a task sent to celery and os installer/package installer
+    will also update its state if needed.
+    """
+    if 'ready' in kwargs and kwargs['ready'] and not clusterhost.state.ready:
+        ready_triggered = True
+    else:
+        ready_triggered = False
+    cluster_ready = False
+    host = clusterhost.host
+    cluster = clusterhost.cluster
+    host_ready = not host.state.ready
+    if ready_triggered:
+        cluster_ready = True
+        for clusterhost_in_cluster in cluster.clusterhosts:
+            if (
+                clusterhost_in_cluster.clusterhost_id
+                    == clusterhost.clusterhost_id
+            ):
+                continue
+            if not clusterhost_in_cluster.state.ready:
+                cluster_ready = False
+
+    logging.info(
+        'clusterhost %s ready: %s',
+        clusterhost.name, ready_triggered
+    )
+    logging.info('cluster ready: %s', cluster_ready)
+    logging.info('host ready: %s', host_ready)
+    if not ready_triggered or from_database_only:
+        logging.info('%s state is set to %s', clusterhost.name, kwargs)
+        utils.update_db_object(session, clusterhost.state, **kwargs)
+        if not clusterhost.state.ready:
+            logging.info('%s state ready is set to False', cluster.name)
+            utils.update_db_object(session, cluster.state, ready=False)
+        status = '%s state is updated' % clusterhost.name
+    else:
+        if not user:
+            user_id = cluster.creator_id
+            user_dict = user_api.get_user(user_id, session=session)
+            user_email = user_dict['email']
+        else:
+            user_email = user.email
+        from compass.tasks import client as celery_client
+        celery_client.celery.send_task(
+            'compass.tasks.package_installed',
+            (
+                clusterhost.cluster_id, clusterhost.host_id,
+                cluster_ready, host_ready
+            ),
+            queue=user_email,
+            exchange=user_email,
+            routing_key=user_email
+        )
+        status = '%s: cluster ready %s host ready %s' % (
+            clusterhost.name, cluster_ready, host_ready
+        )
+        logging.info('action status: %s', status)
+    return {
+        'status': status,
+        'clusterhost': clusterhost.state_dict()
+    }
+
+
+@util.deprecated
+@utils.supported_filters(
+    optional_support_keys=UPDATED_CLUSTERHOST_STATE_INTERNAL_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_CLUSTERHOST_STATE
+)
+@utils.wrap_to_dict(['status', 'clusterhost'])
+def update_cluster_host_state_internal(
+    cluster_id, host_id, from_database_only=False,
+    user=None, session=None, **kwargs
+):
+    """Update a clusterhost state by installation process."""
+    # TODO(xicheng): it should be merged into update_cluster_host_state
+    clusterhost = _get_cluster_host(
+        cluster_id, host_id, session=session
+    )
+    return _update_clusterhost_state(
+        clusterhost, from_database_only=from_database_only,
+        session=session, users=user, **kwargs
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_CLUSTERHOST_STATE_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_CLUSTERHOST_STATE
+)
+@utils.wrap_to_dict(RESP_CLUSTERHOST_STATE_FIELDS)
+def update_clusterhost_state(
+    clusterhost_id, user=None, session=None, **kwargs
+):
+    """Update a clusterhost itself state."""
+    clusterhost = _get_clusterhost(
+        clusterhost_id, session=session
+    )
+    # Modify(harry): without progress_update.py to update cluster state
+    # update cluster state here
+    cluster = _get_cluster(clusterhost.cluster_id, session=session)
+    utils.update_db_object(session, clusterhost.state, **kwargs)
+    utils.update_db_object(session, cluster.state, **kwargs)
+    return clusterhost.state_dict()
+
+
+@util.deprecated
+@utils.supported_filters(
+    optional_support_keys=UPDATED_CLUSTERHOST_STATE_INTERNAL_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_CLUSTERHOST_STATE
+)
+@utils.wrap_to_dict(['status', 'clusterhost'])
+def update_clusterhost_state_internal(
+    clusterhost_id, from_database_only=False,
+    user=None, session=None, **kwargs
+):
+    """Update a clusterhost state by installation process."""
+    # TODO(xicheng): it should be merged into update_clusterhost_state
+    clusterhost = _get_clusterhost(clusterhost_id, session=session)
+    return _update_clusterhost_state(
+        clusterhost, from_database_only=from_database_only,
+        session=session, user=user, **kwargs
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_CLUSTER_STATE_FIELDS,
+    ignore_support_keys=(IGNORE_FIELDS + IGNORE_UPDATED_CLUSTER_STATE_FIELDS)
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_CLUSTER_STATE
+)
+@utils.wrap_to_dict(RESP_STATE_FIELDS)
+def update_cluster_state(
+    cluster_id, user=None, session=None, **kwargs
+):
+    """Update a cluster state."""
+    cluster = _get_cluster(
+        cluster_id, session=session
+    )
+    utils.update_db_object(session, cluster.state, **kwargs)
+    return cluster.state_dict()
+
+
+@util.deprecated
+@utils.supported_filters(
+    optional_support_keys=UPDATED_CLUSTER_STATE_INTERNAL_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_CLUSTER_STATE
+)
+@utils.wrap_to_dict(['status', 'cluster'])
+def update_cluster_state_internal(
+    cluster_id, from_database_only=False,
+    user=None, session=None, **kwargs
+):
+    """Update a cluster state by installation process.
+
+    If from_database_only, the state will only be updated in database.
+    Otherwise a task sent to do state update in os installer and
+    package installer.
+    """
+    # TODO(xicheng): it should be merged into update_cluster_state
+    cluster = _get_cluster(cluster_id, session=session)
+    if 'ready' in kwargs and kwargs['ready'] and not cluster.state.ready:
+        ready_triggered = True
+    else:
+        ready_triggered = False
+    clusterhost_ready = {}
+    if ready_triggered:
+        for clusterhost in cluster.clusterhosts:
+            clusterhost_ready[clusterhost.host_id] = (
+                not clusterhost.state.ready
+            )
+
+    logging.info('cluster %s ready: %s', cluster_id, ready_triggered)
+    logging.info('clusterhost ready: %s', clusterhost_ready)
+
+    if not ready_triggered or from_database_only:
+        logging.info('%s state is set to %s', cluster.name, kwargs)
+        utils.update_db_object(session, cluster.state, **kwargs)
+        if not cluster.state.ready:
+            for clusterhost in cluster.clusterhosts:
+                logging.info('%s state ready is to False', clusterhost.name)
+                utils.update_db_object(
+                    session, clusterhost.state, ready=False
+                )
+        status = '%s state is updated' % cluster.name
+    else:
+        if not user:
+            user_id = cluster.creator_id
+            user_dict = user_api.get_user(user_id, session=session)
+            user_email = user_dict['email']
+        else:
+            user_email = user.email
+        from compass.tasks import client as celery_client
+        celery_client.celery.send_task(
+            'compass.tasks.cluster_installed',
+            (clusterhost.cluster_id, clusterhost_ready),
+            queue=user_email,
+            exchange=user_email,
+            routing_key=user_email
+        )
+        status = '%s installed action set clusterhost ready %s' % (
+            cluster.name, clusterhost_ready
+        )
+        logging.info('action status: %s', status)
+    return {
+        'status': status,
+        'cluster': cluster.state_dict()
+    }
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_CLUSTERHOST_LOG_FIELDS)
+def get_cluster_host_log_histories(
+    cluster_id, host_id, user=None, session=None, **kwargs
+):
+    """Get clusterhost log history by cluster id and host id."""
+    return _get_cluster_host(
+        cluster_id, host_id, session=session
+    ).log_histories
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_CLUSTERHOST_LOG_FIELDS)
+def get_clusterhost_log_histories(
+    clusterhost_id, user=None,
+    session=None, **kwargs
+):
+    """Get clusterhost log history by clusterhost id."""
+    return _get_clusterhost(
+        clusterhost_id, session=session
+    ).log_histories
+
+
+def _get_cluster_host_log_history(
+    cluster_id, host_id, filename, session=None, **kwargs
+):
+    """Get clusterhost log history by cluster id, host id and filename."""
+    clusterhost = _get_cluster_host(cluster_id, host_id, session=session)
+    return utils.get_db_object(
+        session, models.ClusterHostLogHistory,
+        clusterhost_id=clusterhost.clusterhost_id, filename=filename,
+        **kwargs
+    )
+
+
+def _get_clusterhost_log_history(
+    clusterhost_id, filename, session=None, **kwargs
+):
+    """Get clusterhost log history by clusterhost id and filename."""
+    clusterhost = _get_clusterhost(clusterhost_id, session=session)
+    return utils.get_db_object(
+        session, models.ClusterHostLogHistory,
+        clusterhost_id=clusterhost.clusterhost_id, filename=filename,
+        **kwargs
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_CLUSTERHOST_LOG_FIELDS)
+def get_cluster_host_log_history(
+    cluster_id, host_id, filename, user=None, session=None, **kwargs
+):
+    """Get clusterhost log history by cluster id, host id and filename."""
+    return _get_cluster_host_log_history(
+        cluster_id, host_id, filename, session=session
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_CLUSTERHOST_LOG_FIELDS)
+def get_clusterhost_log_history(
+    clusterhost_id, filename, user=None, session=None, **kwargs
+):
+    """Get host log history by clusterhost id and filename."""
+    return _get_clusterhost_log_history(
+        clusterhost_id, filename, session=session
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_CLUSTERHOST_LOG_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_CLUSTERHOST_LOG_FIELDS)
+def update_cluster_host_log_history(
+    cluster_id, host_id, filename, user=None, session=None, **kwargs
+):
+    """Update a host log history by cluster id, host id and filename."""
+    cluster_host_log_history = _get_cluster_host_log_history(
+        cluster_id, host_id, filename, session=session
+    )
+    return utils.update_db_object(
+        session, cluster_host_log_history, **kwargs
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_CLUSTERHOST_LOG_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_CLUSTERHOST_LOG_FIELDS)
+def update_clusterhost_log_history(
+    clusterhost_id, filename, user=None, session=None, **kwargs
+):
+    """Update a host log history by clusterhost id and filename."""
+    clusterhost_log_history = _get_clusterhost_log_history(
+        clusterhost_id, filename, session=session
+    )
+    return utils.update_db_object(session, clusterhost_log_history, **kwargs)
+
+
+@utils.supported_filters(
+    ADDED_CLUSTERHOST_LOG_FIELDS,
+    optional_support_keys=UPDATED_CLUSTERHOST_LOG_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_CLUSTERHOST_LOG_FIELDS)
+def add_clusterhost_log_history(
+    clusterhost_id, exception_when_existing=False,
+    filename=None, user=None, session=None, **kwargs
+):
+    """add a host log history by clusterhost id and filename."""
+    clusterhost = _get_clusterhost(clusterhost_id, session=session)
+    return utils.add_db_object(
+        session, models.ClusterHostLogHistory,
+        exception_when_existing,
+        clusterhost.clusterhost_id, filename, **kwargs
+    )
+
+
+@utils.supported_filters(
+    ADDED_CLUSTERHOST_LOG_FIELDS,
+    optional_support_keys=UPDATED_CLUSTERHOST_LOG_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_CLUSTERHOST_LOG_FIELDS)
+def add_cluster_host_log_history(
+    cluster_id, host_id, exception_when_existing=False,
+    filename=None, user=None, session=None, **kwargs
+):
+    """add a host log history by cluster id, host id and filename."""
+    clusterhost = _get_cluster_host(
+        cluster_id, host_id, session=session
+    )
+    return utils.add_db_object(
+        session, models.ClusterHostLogHistory, exception_when_existing,
+        clusterhost.clusterhost_id, filename, **kwargs
+    )
diff --git a/compass-tasks/db/api/database.py b/compass-tasks/db/api/database.py
new file mode 100644
index 0000000..49769d7
--- /dev/null
+++ b/compass-tasks/db/api/database.py
@@ -0,0 +1,264 @@
+# Copyright 2014 Huawei Technologies Co. Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Provider interface to manipulate database."""
+import functools
+import logging
+import netaddr
+
+from contextlib import contextmanager
+from sqlalchemy import create_engine
+from sqlalchemy.exc import IntegrityError
+from sqlalchemy.exc import OperationalError
+from sqlalchemy.orm import scoped_session
+from sqlalchemy.orm import sessionmaker
+from sqlalchemy.pool import NullPool
+from sqlalchemy.pool import QueuePool
+from sqlalchemy.pool import SingletonThreadPool
+from sqlalchemy.pool import StaticPool
+from threading import local
+
+from compass.db import exception
+from compass.db import models
+from compass.utils import logsetting
+from compass.utils import setting_wrapper as setting
+
+
+ENGINE = None
+SESSION = sessionmaker(autocommit=False, autoflush=False)
+SCOPED_SESSION = None
+SESSION_HOLDER = local()
+
+POOL_MAPPING = {
+    'instant': NullPool,
+    'static': StaticPool,
+    'queued': QueuePool,
+    'thread_single': SingletonThreadPool
+}
+
+
+def init(database_url=None):
+    """Initialize database.
+
+    Adjust sqlalchemy logging if necessary.
+
+    :param database_url: string, database url.
+    """
+    global ENGINE
+    global SCOPED_SESSION
+    if not database_url:
+        database_url = setting.SQLALCHEMY_DATABASE_URI
+    logging.info('init database %s', database_url)
+    root_logger = logging.getLogger()
+    fine_debug = root_logger.isEnabledFor(logsetting.LOGLEVEL_MAPPING['fine'])
+    if fine_debug:
+        logging.getLogger('sqlalchemy.engine').setLevel(logging.INFO)
+    finest_debug = root_logger.isEnabledFor(
+        logsetting.LOGLEVEL_MAPPING['finest']
+    )
+    if finest_debug:
+        logging.getLogger('sqlalchemy.dialects').setLevel(logging.INFO)
+        logging.getLogger('sqlalchemy.pool').setLevel(logging.INFO)
+        logging.getLogger('sqlalchemy.orm').setLevel(logging.INFO)
+    poolclass = POOL_MAPPING[setting.SQLALCHEMY_DATABASE_POOL_TYPE]
+    ENGINE = create_engine(
+        database_url, convert_unicode=True,
+        poolclass=poolclass
+    )
+    SESSION.configure(bind=ENGINE)
+    SCOPED_SESSION = scoped_session(SESSION)
+    models.BASE.query = SCOPED_SESSION.query_property()
+
+
+def in_session():
+    """check if in database session scope."""
+    bool(hasattr(SESSION_HOLDER, 'session'))
+
+
+@contextmanager
+def session(exception_when_in_session=True):
+    """database session scope.
+
+    To operate database, it should be called in database session.
+    If not exception_when_in_session, the with session statement support
+    nested session and only the out most session commit/rollback the
+    transaction.
+    """
+    if not ENGINE:
+        init()
+
+    nested_session = False
+    if hasattr(SESSION_HOLDER, 'session'):
+        if exception_when_in_session:
+            logging.error('we are already in session')
+            raise exception.DatabaseException('session already exist')
+        else:
+            new_session = SESSION_HOLDER.session
+            nested_session = True
+            logging.log(
+                logsetting.getLevelByName('fine'),
+                'reuse session %s', nested_session
+            )
+    else:
+        new_session = SCOPED_SESSION()
+        setattr(SESSION_HOLDER, 'session', new_session)
+        logging.log(
+            logsetting.getLevelByName('fine'),
+            'enter session %s', new_session
+        )
+    try:
+        yield new_session
+        if not nested_session:
+            new_session.commit()
+    except Exception as error:
+        if not nested_session:
+            new_session.rollback()
+            logging.error('failed to commit session')
+        logging.exception(error)
+        if isinstance(error, IntegrityError):
+            for item in error.statement.split():
+                if item.islower():
+                    object = item
+                    break
+            raise exception.DuplicatedRecord(
+                '%s in %s' % (error.orig, object)
+            )
+        elif isinstance(error, OperationalError):
+            raise exception.DatabaseException(
+                'operation error in database'
+            )
+        elif isinstance(error, exception.DatabaseException):
+            raise error
+        else:
+            raise exception.DatabaseException(str(error))
+    finally:
+        if not nested_session:
+            new_session.close()
+            SCOPED_SESSION.remove()
+            delattr(SESSION_HOLDER, 'session')
+        logging.log(
+            logsetting.getLevelByName('fine'),
+            'exit session %s', new_session
+        )
+
+
+def current_session():
+    """Get the current session scope when it is called.
+
+       :return: database session.
+       :raises: DatabaseException when it is not in session.
+    """
+    try:
+        return SESSION_HOLDER.session
+    except Exception as error:
+        logging.error('It is not in the session scope')
+        logging.exception(error)
+        if isinstance(error, exception.DatabaseException):
+            raise error
+        else:
+            raise exception.DatabaseException(str(error))
+
+
+def run_in_session(exception_when_in_session=True):
+    """Decorator to make sure the decorated function run in session.
+
+    When not exception_when_in_session, the run_in_session can be
+    decorated several times.
+    """
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            try:
+                my_session = kwargs.get('session')
+                if my_session is not None:
+                    return func(*args, **kwargs)
+                else:
+                    with session(
+                        exception_when_in_session=exception_when_in_session
+                    ) as my_session:
+                        kwargs['session'] = my_session
+                        return func(*args, **kwargs)
+            except Exception as error:
+                logging.error(
+                    'got exception with func %s args %s kwargs %s',
+                    func, args, kwargs
+                )
+                logging.exception(error)
+                raise error
+        return wrapper
+    return decorator
+
+
+def _setup_user_table(user_session):
+    """Initialize user table with default user."""
+    logging.info('setup user table')
+    from compass.db.api import user
+    user.add_user(
+        session=user_session,
+        email=setting.COMPASS_ADMIN_EMAIL,
+        password=setting.COMPASS_ADMIN_PASSWORD,
+        is_admin=True
+    )
+
+
+def _setup_permission_table(permission_session):
+    """Initialize permission table."""
+    logging.info('setup permission table.')
+    from compass.db.api import permission
+    permission.add_permissions_internal(
+        session=permission_session
+    )
+
+
+def _setup_switch_table(switch_session):
+    """Initialize switch table."""
+    # TODO(xicheng): deprecate setup default switch.
+    logging.info('setup switch table')
+    from compass.db.api import switch
+    switch.add_switch(
+        True, setting.DEFAULT_SWITCH_IP,
+        session=switch_session,
+        machine_filters=['allow ports all']
+    )
+
+
+def _update_others(other_session):
+    """Update other tables."""
+    logging.info('update other tables')
+    from compass.db.api import utils
+    from compass.db import models
+    utils.update_db_objects(
+        other_session, models.Cluster
+    )
+    utils.update_db_objects(
+        other_session, models.Host
+    )
+    utils.update_db_objects(
+        other_session, models.ClusterHost
+    )
+
+
+@run_in_session()
+def create_db(session=None):
+    """Create database."""
+    models.BASE.metadata.create_all(bind=ENGINE)
+    _setup_permission_table(session)
+    _setup_user_table(session)
+    _setup_switch_table(session)
+    _update_others(session)
+
+
+def drop_db():
+    """Drop database."""
+    models.BASE.metadata.drop_all(bind=ENGINE)
diff --git a/compass-tasks/db/api/health_check_report.py b/compass-tasks/db/api/health_check_report.py
new file mode 100644
index 0000000..aaea7a7
--- /dev/null
+++ b/compass-tasks/db/api/health_check_report.py
@@ -0,0 +1,190 @@
+# Copyright 2014 Huawei Technologies Co. Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Cluster health check report."""
+import logging
+
+from compass.db.api import cluster as cluster_api
+from compass.db.api import database
+from compass.db.api import host as host_api
+from compass.db.api import permission
+from compass.db.api import user as user_api
+from compass.db.api import utils
+from compass.db import exception
+from compass.db import models
+
+
+REQUIRED_INSERT_FIELDS = ['name']
+OPTIONAL_INSERT_FIELDS = [
+    'display_name', 'report', 'category', 'state', 'error_message'
+]
+UPDATE_FIELDS = ['report', 'state', 'error_message']
+RESP_FIELDS = [
+    'cluster_id', 'name', 'display_name', 'report',
+    'category', 'state', 'error_message'
+]
+RESP_ACTION_FIELDS = ['cluster_id', 'status']
+
+
+@utils.supported_filters(REQUIRED_INSERT_FIELDS, OPTIONAL_INSERT_FIELDS)
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_FIELDS)
+def add_report_record(cluster_id, name=None, report={},
+                      state='verifying', session=None, **kwargs):
+    """Create a health check report record."""
+    # Replace any white space into '-'
+    words = name.split()
+    name = '-'.join(words)
+    cluster = cluster_api.get_cluster_internal(cluster_id, session=session)
+    return utils.add_db_object(
+        session, models.HealthCheckReport, True, cluster.id, name,
+        report=report, state=state, **kwargs
+    )
+
+
+def _get_report(cluster_id, name, session=None):
+    cluster = cluster_api.get_cluster_internal(cluster_id, session=session)
+    return utils.get_db_object(
+        session, models.HealthCheckReport, cluster_id=cluster.id, name=name
+    )
+
+
+@utils.supported_filters(UPDATE_FIELDS)
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_FIELDS)
+def update_report(cluster_id, name, session=None, **kwargs):
+    """Update health check report."""
+    report = _get_report(cluster_id, name, session=session)
+    if report.state == 'finished':
+        err_msg = 'Report cannot be updated if state is in "finished"'
+        raise exception.Forbidden(err_msg)
+
+    return utils.update_db_object(session, report, **kwargs)
+
+
+@utils.supported_filters(UPDATE_FIELDS)
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_FIELDS)
+def update_multi_reports(cluster_id, session=None, **kwargs):
+    """Bulk update reports."""
+    # TODO(grace): rename the fuction if needed to reflect the fact.
+    return set_error(cluster_id, session=session, **kwargs)
+
+
+def set_error(cluster_id, report={}, session=None,
+              state='error', error_message=None):
+    cluster = cluster_api.get_cluster_internal(cluster_id, session=session)
+    logging.debug(
+        "updates all reports as %s in cluster %s",
+        state, cluster_id
+    )
+    return utils.update_db_objects(
+        session, models.HealthCheckReport,
+        updates={
+            'report': {},
+            'state': 'error',
+            'error_message': error_message
+        }, cluster_id=cluster.id
+    )
+
+
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_HEALTH_REPORT
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def list_health_reports(cluster_id, user=None, session=None):
+    """List all reports in the specified cluster."""
+    cluster = cluster_api.get_cluster_internal(cluster_id, session=session)
+    return utils.list_db_objects(
+        session, models.HealthCheckReport, cluster_id=cluster.id
+    )
+
+
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_GET_HEALTH_REPORT
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def get_health_report(cluster_id, name, user=None, session=None):
+    return _get_report(
+        cluster_id, name, session=session
+    )
+
+
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DELETE_REPORT
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def delete_reports(cluster_id, name=None, user=None, session=None):
+    # TODO(grace): better to separate this function into two.
+    # One is to delete a report of a cluster, the other to delete all
+    # reports under a cluster.
+    if name:
+        report = _get_report(cluster_id, name, session=session)
+        return utils.del_db_object(session, report)
+    else:
+        cluster = cluster_api.get_cluster_internal(
+            cluster_id, session=session
+        )
+        return utils.del_db_objects(
+            session, models.HealthCheckReport, cluster_id=cluster.id
+        )
+
+
+@utils.supported_filters(optional_support_keys=['check_health'])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_CHECK_CLUSTER_HEALTH
+)
+@utils.wrap_to_dict(RESP_ACTION_FIELDS)
+def start_check_cluster_health(cluster_id, send_report_url,
+                               user=None, session=None, check_health={}):
+    """Start to check cluster health."""
+    cluster = cluster_api.get_cluster_internal(cluster_id, session=session)
+
+    if cluster.state.state != 'SUCCESSFUL':
+        logging.debug("state is %s" % cluster.state.state)
+        err_msg = "Healthcheck starts only after cluster finished deployment!"
+        raise exception.Forbidden(err_msg)
+
+    reports = utils.list_db_objects(
+        session, models.HealthCheckReport,
+        cluster_id=cluster.id, state='verifying'
+    )
+    if reports:
+        err_msg = 'Healthcheck in progress, please wait for it to complete!'
+        raise exception.Forbidden(err_msg)
+
+    # Clear all preivous report
+    # TODO(grace): the delete should be moved into celery task.
+    # We should consider the case that celery task is down.
+    utils.del_db_objects(
+        session, models.HealthCheckReport, cluster_id=cluster.id
+    )
+
+    from compass.tasks import client as celery_client
+    celery_client.celery.send_task(
+        'compass.tasks.cluster_health',
+        (cluster.id, send_report_url, user.email),
+        queue=user.email,
+        exchange=user.email,
+        routing_key=user.email
+    )
+    return {
+        "cluster_id": cluster.id,
+        "status": "start to check cluster health."
+    }
diff --git a/compass-tasks/db/api/host.py b/compass-tasks/db/api/host.py
new file mode 100644
index 0000000..15e0bb6
--- /dev/null
+++ b/compass-tasks/db/api/host.py
@@ -0,0 +1,1120 @@
+# Copyright 2014 Huawei Technologies Co. Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Host database operations."""
+import functools
+import logging
+import netaddr
+import re
+
+from compass.db.api import database
+from compass.db.api import metadata_holder as metadata_api
+from compass.db.api import permission
+from compass.db.api import user as user_api
+from compass.db.api import utils
+from compass.db import exception
+from compass.db import models
+from compass.utils import util
+
+
+SUPPORTED_FIELDS = ['name', 'os_name', 'owner', 'mac', 'id']
+SUPPORTED_MACHINE_HOST_FIELDS = [
+    'mac', 'tag', 'location', 'os_name', 'os_id'
+]
+SUPPORTED_NETOWORK_FIELDS = [
+    'interface', 'ip', 'is_mgmt', 'is_promiscuous'
+]
+RESP_FIELDS = [
+    'id', 'name', 'hostname', 'os_name', 'owner', 'mac',
+    'switch_ip', 'port', 'switches', 'os_installer', 'os_id', 'ip',
+    'reinstall_os', 'os_installed', 'tag', 'location', 'networks',
+    'created_at', 'updated_at'
+]
+RESP_CLUSTER_FIELDS = [
+    'id', 'name', 'os_name', 'reinstall_distributed_system',
+    'owner', 'adapter_name', 'flavor_name',
+    'distributed_system_installed', 'created_at', 'updated_at'
+]
+RESP_NETWORK_FIELDS = [
+    'id', 'ip', 'interface', 'netmask', 'is_mgmt', 'is_promiscuous',
+    'created_at', 'updated_at'
+]
+RESP_CONFIG_FIELDS = [
+    'os_config',
+    'config_setp',
+    'config_validated',
+    'networks',
+    'created_at',
+    'updated_at'
+]
+RESP_DEPLOYED_CONFIG_FIELDS = [
+    'deployed_os_config'
+]
+RESP_DEPLOY_FIELDS = [
+    'status', 'host'
+]
+UPDATED_FIELDS = ['name', 'reinstall_os']
+UPDATED_CONFIG_FIELDS = [
+    'put_os_config'
+]
+PATCHED_CONFIG_FIELDS = [
+    'patched_os_config'
+]
+UPDATED_DEPLOYED_CONFIG_FIELDS = [
+    'deployed_os_config'
+]
+ADDED_NETWORK_FIELDS = [
+    'interface', 'ip', 'subnet_id'
+]
+OPTIONAL_ADDED_NETWORK_FIELDS = ['is_mgmt', 'is_promiscuous']
+UPDATED_NETWORK_FIELDS = [
+    'interface', 'ip', 'subnet_id', 'subnet', 'is_mgmt',
+    'is_promiscuous'
+]
+IGNORE_FIELDS = [
+    'id', 'created_at', 'updated_at'
+]
+RESP_STATE_FIELDS = [
+    'id', 'state', 'percentage', 'message', 'severity', 'ready'
+]
+UPDATED_STATE_FIELDS = [
+    'state', 'percentage', 'message', 'severity'
+]
+UPDATED_STATE_INTERNAL_FIELDS = [
+    'ready'
+]
+RESP_LOG_FIELDS = [
+    'id', 'filename', 'position', 'partial_line', 'percentage',
+    'message', 'severity', 'line_matcher_name'
+]
+ADDED_LOG_FIELDS = [
+    'filename'
+]
+UPDATED_LOG_FIELDS = [
+    'position', 'partial_line', 'percentage',
+    'message', 'severity', 'line_matcher_name'
+]
+
+
+@utils.supported_filters(optional_support_keys=SUPPORTED_FIELDS)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_HOSTS
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def list_hosts(user=None, session=None, **filters):
+    """List hosts."""
+    return utils.list_db_objects(
+        session, models.Host, **filters
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=SUPPORTED_MACHINE_HOST_FIELDS)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_HOSTS
+)
+@utils.output_filters(
+    missing_ok=True,
+    tag=utils.general_filter_callback,
+    location=utils.general_filter_callback,
+    os_name=utils.general_filter_callback,
+    os_id=utils.general_filter_callback
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def list_machines_or_hosts(user=None, session=None, **filters):
+    """List machines or hosts if possible."""
+    machines = utils.list_db_objects(
+        session, models.Machine, **filters
+    )
+    machines_or_hosts = []
+    for machine in machines:
+        host = machine.host
+        if host:
+            machines_or_hosts.append(host)
+        else:
+            machines_or_hosts.append(machine)
+    return machines_or_hosts
+
+
+def _get_host(host_id, session=None, **kwargs):
+    """Get host by id."""
+    if isinstance(host_id, (int, long)):
+        return utils.get_db_object(
+            session, models.Host,
+            id=host_id, **kwargs
+        )
+    else:
+        raise exception.InvalidParameter(
+            'host id %s type is not int compatible' % host_id
+        )
+
+
+def get_host_internal(host_id, session=None, **kwargs):
+    """Helper function to get host.
+
+    Used by other files under db/api.
+    """
+    return _get_host(host_id, session=session, **kwargs)
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_HOSTS
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def get_host(
+    host_id, exception_when_missing=True,
+    user=None, session=None, **kwargs
+):
+    """get host info."""
+    return _get_host(
+        host_id,
+        exception_when_missing=exception_when_missing,
+        session=session
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_HOSTS
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def get_machine_or_host(
+    host_id, exception_when_missing=True,
+    user=None, session=None, **kwargs
+):
+    """get machine or host if possible."""
+    from compass.db.api import machine as machine_api
+    machine = machine_api.get_machine_internal(
+        host_id,
+        exception_when_missing=exception_when_missing,
+        session=session
+    )
+    if machine.host:
+        return machine.host
+    else:
+        return machine
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_HOST_CLUSTERS
+)
+@utils.wrap_to_dict(RESP_CLUSTER_FIELDS)
+def get_host_clusters(host_id, user=None, session=None, **kwargs):
+    """get host clusters."""
+    host = _get_host(host_id, session=session)
+    return [clusterhost.cluster for clusterhost in host.clusterhosts]
+
+
+def check_host_validated(host):
+    """Check host is validated."""
+    if not host.config_validated:
+        raise exception.Forbidden(
+            'host %s is not validated' % host.name
+        )
+
+
+def check_host_editable(
+    host, user=None,
+    check_in_installing=False
+):
+    """Check host is editable.
+
+    If we try to set reinstall_os or check the host is not in installing
+    state, we should set check_in_installing to True.
+    Otherwise we will check the host is not in installing or installed.
+    We also make sure the user is admin or the owner of the host to avoid
+    unauthorized user to update host attributes.
+    """
+    if check_in_installing:
+        if host.state.state == 'INSTALLING':
+            raise exception.Forbidden(
+                'host %s is not editable '
+                'when state is in installing' % host.name
+            )
+    elif not host.reinstall_os:
+        raise exception.Forbidden(
+            'host %s is not editable '
+            'when not to be reinstalled' % host.name
+        )
+    if user and not user.is_admin and host.creator_id != user.id:
+        raise exception.Forbidden(
+            'host %s is not editable '
+            'when user is not admin or the owner of the host' % host.name
+        )
+
+
+def is_host_editable(
+    host, user=None,
+    check_in_installing=False
+):
+    """Get if host is editable."""
+    try:
+        check_host_editable(
+            host, user=user,
+            check_in_installing=check_in_installing
+        )
+        return True
+    except exception.Forbidden:
+        return False
+
+
+def validate_host(host):
+    """Validate host.
+
+    Makesure hostname is not empty, there is only one mgmt network,
+    The mgmt network is not in promiscuous mode.
+    """
+    if not host.hostname:
+        raise exception.Invalidparameter(
+            'host %s does not set hostname' % host.name
+        )
+    if not host.host_networks:
+        raise exception.InvalidParameter(
+            'host %s does not have any network' % host.name
+        )
+    mgmt_interface_set = False
+    for host_network in host.host_networks:
+        if host_network.is_mgmt:
+            if mgmt_interface_set:
+                raise exception.InvalidParameter(
+                    'host %s multi interfaces set mgmt ' % host.name
+                )
+            if host_network.is_promiscuous:
+                raise exception.InvalidParameter(
+                    'host %s interface %s is mgmt but promiscuous' % (
+                        host.name, host_network.interface
+                    )
+                )
+            mgmt_interface_set = True
+    if not mgmt_interface_set:
+        raise exception.InvalidParameter(
+            'host %s has no mgmt interface' % host.name
+        )
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(name=utils.check_name)
+@utils.wrap_to_dict(RESP_FIELDS)
+def _update_host(host_id, session=None, user=None, **kwargs):
+    """Update a host internal."""
+    host = _get_host(host_id, session=session)
+    if host.state.state == "SUCCESSFUL" and not host.reinstall_os:
+        logging.info("ignoring successful host: %s", host_id)
+        return {}
+    check_host_editable(
+        host, user=user,
+        check_in_installing=kwargs.get('reinstall_os', False)
+    )
+    return utils.update_db_object(session, host, **kwargs)
+
+
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_HOST
+)
+def update_host(host_id, user=None, session=None, **kwargs):
+    """Update a host."""
+    return _update_host(host_id, session=session, user=user, **kwargs)
+
+
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_HOST
+)
+def update_hosts(data=[], user=None, session=None):
+    """Update hosts."""
+    # TODO(xicheng): this batch function is not similar as others.
+    # try to make it similar output as others and batch update should
+    # tolerate partial failure.
+    hosts = []
+    for host_data in data:
+        hosts.append(_update_host(session=session, user=user, **host_data))
+    return hosts
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEL_HOST
+)
+@utils.wrap_to_dict(
+    RESP_FIELDS + ['status', 'host'],
+    host=RESP_FIELDS
+)
+def del_host(
+    host_id, force=False, from_database_only=False,
+    user=None, session=None, **kwargs
+):
+    """Delete a host.
+
+    If force, we delete the host anyway.
+    If from_database_only, we only delete the host record in databaes.
+    Otherwise we send to del host task to celery to delete the host
+    record in os installer and package installer, clean installation logs
+    and at last clean database record.
+    The backend will call this function again after it deletes the record
+    in os installer and package installer with from_database_only set.
+    """
+    from compass.db.api import cluster as cluster_api
+    host = _get_host(host_id, session=session)
+    # force set host state to ERROR when we want to delete the
+    # host anyway even the host is in installing or already
+    # installed. It let the api know the deleting is in doing when backend
+    # is doing the real deleting. In future we may import a new state like
+    # INDELETE to indicate the deleting is processing.
+    # We need discuss about if we can delete a host when it is already
+    # installed by api.
+    if host.state.state != 'UNINITIALIZED' and force:
+        host.state.state = 'ERROR'
+    check_host_editable(
+        host, user=user,
+        check_in_installing=True
+    )
+    cluster_ids = []
+    for clusterhost in host.clusterhosts:
+        if clusterhost.state.state != 'UNINITIALIZED' and force:
+            clusterhost.state.state = 'ERROR'
+        # TODO(grace): here we check all clusters which use this host editable.
+        # Because in backend we do not have functions to delete host without
+        # reference its cluster. After deleting pure host supported in backend,
+        # we should change code here to is_cluster_editable.
+        # Here delete a host may fail even we set force flag.
+        cluster_api.check_cluster_editable(
+            clusterhost.cluster, user=user,
+            check_in_installing=True
+        )
+        cluster_ids.append(clusterhost.cluster_id)
+
+    # Delete host record directly if there is no need to delete it
+    # in backend or from_database_only is set.
+    if host.state.state == 'UNINITIALIZED' or from_database_only:
+        return utils.del_db_object(session, host)
+    else:
+        logging.info(
+            'send del host %s task to celery', host_id
+        )
+        if not user:
+            user_id = host.creator_id
+            user_dict = user_api.get_user(user_id, session=session)
+            user_email = user_dict['email']
+        else:
+            user_email = user.email
+        from compass.tasks import client as celery_client
+        celery_client.celery.send_task(
+            'compass.tasks.delete_host',
+            (
+                user.email, host.id, cluster_ids
+            ),
+            queue=user_email,
+            exchange=user_email,
+            routing_key=user_email
+        )
+        return {
+            'status': 'delete action sent',
+            'host': host,
+        }
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_HOST_CONFIG
+)
+@utils.wrap_to_dict(RESP_CONFIG_FIELDS)
+def get_host_config(host_id, user=None, session=None, **kwargs):
+    """Get host config."""
+    return _get_host(host_id, session=session)
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_HOST_CONFIG
+)
+@utils.wrap_to_dict(RESP_DEPLOYED_CONFIG_FIELDS)
+def get_host_deployed_config(host_id, user=None, session=None, **kwargs):
+    """Get host deployed config."""
+    return _get_host(host_id, session=session)
+
+
+# replace os_config to deployed_os_config in kwargs.
+@utils.replace_filters(
+    os_config='deployed_os_config'
+)
+@utils.supported_filters(
+    UPDATED_DEPLOYED_CONFIG_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_HOST_CONFIG
+)
+@utils.wrap_to_dict(RESP_CONFIG_FIELDS)
+def update_host_deployed_config(host_id, user=None, session=None, **kwargs):
+    """Update host deployed config."""
+    host = _get_host(host_id, session=session)
+    check_host_editable(host, user=user)
+    check_host_validated(host)
+    return utils.update_db_object(session, host, **kwargs)
+
+
+def _host_os_config_validates(
+    config, host, session=None, user=None, **kwargs
+):
+    """Check host os config's validation."""
+    metadata_api.validate_os_config(
+        config, host.os_id
+    )
+
+
+@utils.input_validates_with_args(
+    put_os_config=_host_os_config_validates
+)
+@utils.output_validates_with_args(
+    os_config=_host_os_config_validates
+)
+@utils.wrap_to_dict(RESP_CONFIG_FIELDS)
+def _update_host_config(host, session=None, user=None, **kwargs):
+    """Update host config."""
+    check_host_editable(host, user=user)
+    return utils.update_db_object(session, host, **kwargs)
+
+
+# replace os_config to put_os_config in kwargs.
+# It tells db the os_config will be updated not patched.
+@utils.replace_filters(
+    os_config='put_os_config'
+)
+@utils.supported_filters(
+    UPDATED_CONFIG_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_HOST_CONFIG
+)
+def update_host_config(host_id, user=None, session=None, **kwargs):
+    """Update host config."""
+    host = _get_host(host_id, session=session)
+    return _update_host_config(
+        host, session=session, user=user, **kwargs
+    )
+
+
+# replace os_config to patched_os_config in kwargs.
+# It tells db os_config will be patched not be updated.
+@utils.replace_filters(
+    os_config='patched_os_config'
+)
+@utils.supported_filters(
+    PATCHED_CONFIG_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_HOST_CONFIG
+)
+def patch_host_config(host_id, user=None, session=None, **kwargs):
+    """Patch host config."""
+    host = _get_host(host_id, session=session)
+    return _update_host_config(
+        host, session=session, user=user, **kwargs
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEL_HOST_CONFIG
+)
+@utils.wrap_to_dict(RESP_CONFIG_FIELDS)
+def del_host_config(host_id, user=None, session=None):
+    """delete a host config."""
+    host = _get_host(host_id, session=session)
+    check_host_editable(host, user=user)
+    return utils.update_db_object(
+        session, host, os_config={}, config_validated=False
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=SUPPORTED_NETOWORK_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_HOST_NETWORKS
+)
+@utils.wrap_to_dict(RESP_NETWORK_FIELDS)
+def list_host_networks(host_id, user=None, session=None, **filters):
+    """Get host networks for a host."""
+    host = _get_host(host_id, session=session)
+    return utils.list_db_objects(
+        session, models.HostNetwork,
+        host_id=host.id, **filters
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=SUPPORTED_NETOWORK_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_HOST_NETWORKS
+)
+@utils.wrap_to_dict(RESP_NETWORK_FIELDS)
+def list_hostnetworks(user=None, session=None, **filters):
+    """Get host networks."""
+    return utils.list_db_objects(
+        session, models.HostNetwork, **filters
+    )
+
+
+def _get_hostnetwork(host_network_id, session=None, **kwargs):
+    """Get hostnetwork by hostnetwork id."""
+    if isinstance(host_network_id, (int, long)):
+        return utils.get_db_object(
+            session, models.HostNetwork,
+            id=host_network_id, **kwargs
+        )
+    raise exception.InvalidParameter(
+        'host network id %s type is not int compatible' % host_network_id
+    )
+
+
+def _get_host_network(host_id, host_network_id, session=None, **kwargs):
+    """Get hostnetwork by host id and hostnetwork id."""
+    host = _get_host(host_id, session=session)
+    host_network = _get_hostnetwork(host_network_id, session=session, **kwargs)
+    if host_network.host_id != host.id:
+        raise exception.RecordNotExists(
+            'host %s does not own host network %s' % (
+                host.id, host_network.id
+            )
+        )
+    return host_network
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_HOST_NETWORKS
+)
+@utils.wrap_to_dict(RESP_NETWORK_FIELDS)
+def get_host_network(
+    host_id, host_network_id,
+    user=None, session=None, **kwargs
+):
+    """Get host network."""
+    return _get_host_network(
+        host_id, host_network_id, session=session
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_HOST_NETWORKS
+)
+@utils.wrap_to_dict(RESP_NETWORK_FIELDS)
+def get_hostnetwork(host_network_id, user=None, session=None, **kwargs):
+    """Get host network."""
+    return _get_hostnetwork(host_network_id, session=session)
+
+
+@utils.supported_filters(
+    ADDED_NETWORK_FIELDS,
+    optional_support_keys=OPTIONAL_ADDED_NETWORK_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(
+    ip=utils.check_ip
+)
+@utils.wrap_to_dict(RESP_NETWORK_FIELDS)
+def _add_host_network(
+    host_id, exception_when_existing=True,
+    session=None, user=None, interface=None, ip=None, **kwargs
+):
+    """Add hostnetwork to a host."""
+    host = _get_host(host_id, session=session)
+    check_host_editable(host, user=user)
+    user_id = user.id
+    return utils.add_db_object(
+        session, models.HostNetwork,
+        exception_when_existing,
+        host.id, interface, user_id, ip=ip, **kwargs
+    )
+
+
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_HOST_NETWORK
+)
+def add_host_network(
+    host_id, exception_when_existing=True,
+    interface=None, user=None, session=None, **kwargs
+):
+    """Create a hostnetwork to a host."""
+    return _add_host_network(
+        host_id,
+        exception_when_existing,
+        interface=interface, session=session, user=user, **kwargs
+    )
+
+
+def _get_hostnetwork_by_ip(
+    ip, session=None, **kwargs
+):
+    ip_int = long(netaddr.IPAddress(ip))
+    return utils.get_db_object(
+        session, models.HostNetwork,
+        ip_int=ip_int, **kwargs
+    )
+
+
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_HOST_NETWORK
+)
+def add_host_networks(
+    exception_when_existing=False,
+    data=[], user=None, session=None
+):
+    """Create host networks."""
+    hosts = []
+    failed_hosts = []
+    for host_data in data:
+        host_id = host_data['host_id']
+        host = _get_host(host_id, session=session)
+        networks = host_data['networks']
+        host_networks = []
+        failed_host_networks = []
+        for network in networks:
+            host_network = _get_hostnetwork_by_ip(
+                network['ip'], session=session,
+                exception_when_missing=False
+            )
+            if (
+                host_network and not (
+                    host_network.host_id == host.id and
+                    host_network.interface == network['interface']
+                )
+            ):
+                logging.error('ip %s exists in host network %s' % (
+                    network['ip'], host_network.id
+                ))
+                failed_host_networks.append(network)
+            else:
+                host_networks.append(_add_host_network(
+                    host.id, exception_when_existing,
+                    session=session, user=user, **network
+                ))
+        if host_networks:
+            hosts.append({'host_id': host.id, 'networks': host_networks})
+        if failed_host_networks:
+            failed_hosts.append({
+                'host_id': host.id, 'networks': failed_host_networks
+            })
+    return {
+        'hosts': hosts,
+        'failed_hosts': failed_hosts
+    }
+
+
+@utils.wrap_to_dict(RESP_NETWORK_FIELDS)
+def _update_host_network(
+    host_network, session=None, user=None, **kwargs
+):
+    """Update host network."""
+    check_host_editable(host_network.host, user=user)
+    return utils.update_db_object(session, host_network, **kwargs)
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_NETWORK_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(
+    ip=utils.check_ip
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_HOST_NETWORK
+)
+def update_host_network(
+    host_id, host_network_id, user=None, session=None, **kwargs
+):
+    """Update a host network by host id and host network id."""
+    host = _get_host(
+        host_id, session=session
+    )
+    if host.state.state == "SUCCESSFUL" and not host.reinstall_os:
+        logging.info("ignoring updating request for successful hosts")
+        return {}
+
+    host_network = _get_host_network(
+        host_id, host_network_id, session=session
+    )
+    return _update_host_network(
+        host_network, session=session, user=user, **kwargs
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_NETWORK_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(
+    ip=utils.check_ip
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_HOST_NETWORK
+)
+def update_hostnetwork(host_network_id, user=None, session=None, **kwargs):
+    """Update a host network by host network id."""
+    host_network = _get_hostnetwork(
+        host_network_id, session=session
+    )
+    return _update_host_network(
+        host_network, session=session, user=user, **kwargs
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEL_HOST_NETWORK
+)
+@utils.wrap_to_dict(RESP_NETWORK_FIELDS)
+def del_host_network(
+    host_id, host_network_id, user=None,
+    session=None, **kwargs
+):
+    """Delete a host network by host id and host network id."""
+    host_network = _get_host_network(
+        host_id, host_network_id, session=session
+    )
+    check_host_editable(host_network.host, user=user)
+    return utils.del_db_object(session, host_network)
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEL_HOST_NETWORK
+)
+@utils.wrap_to_dict(RESP_NETWORK_FIELDS)
+def del_hostnetwork(host_network_id, user=None, session=None, **kwargs):
+    """Delete a host network by host network id."""
+    host_network = _get_hostnetwork(
+        host_network_id, session=session
+    )
+    check_host_editable(host_network.host, user=user)
+    return utils.del_db_object(session, host_network)
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_GET_HOST_STATE
+)
+@utils.wrap_to_dict(RESP_STATE_FIELDS)
+def get_host_state(host_id, user=None, session=None, **kwargs):
+    """Get host state info."""
+    return _get_host(host_id, session=session).state
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_STATE_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_HOST_STATE
+)
+@utils.wrap_to_dict(RESP_STATE_FIELDS)
+def update_host_state(host_id, user=None, session=None, **kwargs):
+    """Update a host state."""
+    host = _get_host(host_id, session=session)
+    utils.update_db_object(session, host.state, **kwargs)
+    return host.state
+
+
+@util.deprecated
+@utils.supported_filters(
+    optional_support_keys=UPDATED_STATE_INTERNAL_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_HOST_STATE
+)
+@utils.wrap_to_dict(['status', 'host'])
+def update_host_state_internal(
+    host_id, from_database_only=False,
+    user=None, session=None, **kwargs
+):
+    """Update a host state.
+
+    This function is called when host os is installed.
+    If from_database_only, the state is updated in database.
+    Otherwise a celery task sent to os installer and package installer
+    to do some future actions.
+    """
+    # TODO(xicheng): should be merged into update_host_state
+    host = _get_host(host_id, session=session)
+    logging.info("======host state: %s", host.state)
+    if 'ready' in kwargs and kwargs['ready'] and not host.state.ready:
+        ready_triggered = True
+    else:
+        ready_triggered = False
+    clusterhosts_ready = {}
+    clusters_os_ready = {}
+    if ready_triggered:
+        for clusterhost in host.clusterhosts:
+            cluster = clusterhost.cluster
+            if cluster.flavor_name:
+                clusterhosts_ready[cluster.id] = False
+            else:
+                clusterhosts_ready[cluster.id] = True
+            all_os_ready = True
+            for clusterhost_in_cluster in cluster.clusterhosts:
+                host_in_cluster = clusterhost_in_cluster.host
+                if host_in_cluster.id == host.id:
+                    continue
+                if not host_in_cluster.state.ready:
+                    all_os_ready = False
+            clusters_os_ready[cluster.id] = all_os_ready
+    logging.debug('host %s ready: %s', host_id, ready_triggered)
+    logging.debug("clusterhosts_ready is: %s", clusterhosts_ready)
+    logging.debug("clusters_os_ready is %s", clusters_os_ready)
+
+    if not ready_triggered or from_database_only:
+        logging.debug('%s state is set to %s', host.name, kwargs)
+        utils.update_db_object(session, host.state, **kwargs)
+        if not host.state.ready:
+            for clusterhost in host.clusterhosts:
+                utils.update_db_object(
+                    session, clusterhost.state, ready=False
+                )
+                utils.update_db_object(
+                    session, clusterhost.cluster.state, ready=False
+                )
+        status = '%s state is updated' % host.name
+    else:
+        if not user:
+            user_id = host.creator_id
+            user_dict = user_api.get_user(user_id, session=session)
+            user_email = user_dict['email']
+        else:
+            user_email = user.email
+        from compass.tasks import client as celery_client
+        celery_client.celery.send_task(
+            'compass.tasks.os_installed',
+            (
+                host.id, clusterhosts_ready,
+                clusters_os_ready
+            ),
+            queue=user_email,
+            exchange=user_email,
+            routing_key=user_email
+        )
+        status = '%s: clusterhosts ready %s clusters os ready %s' % (
+            host.name, clusterhosts_ready, clusters_os_ready
+        )
+        logging.info('action status: %s', status)
+    return {
+        'status': status,
+        'host': host.state
+    }
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_LOG_FIELDS)
+def get_host_log_histories(host_id, user=None, session=None, **kwargs):
+    """Get host log history."""
+    host = _get_host(host_id, session=session)
+    return utils.list_db_objects(
+        session, models.HostLogHistory, id=host.id, **kwargs
+    )
+
+
+def _get_host_log_history(host_id, filename, session=None, **kwargs):
+    host = _get_host(host_id, session=session)
+    return utils.get_db_object(
+        session, models.HostLogHistory, id=host.id,
+        filename=filename, **kwargs
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_LOG_FIELDS)
+def get_host_log_history(host_id, filename, user=None, session=None, **kwargs):
+    """Get host log history."""
+    return _get_host_log_history(
+        host_id, filename, session=session
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_LOG_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_LOG_FIELDS)
+def update_host_log_history(
+    host_id, filename, user=None,
+    session=None, **kwargs
+):
+    """Update a host log history."""
+    host_log_history = _get_host_log_history(
+        host_id, filename, session=session
+    )
+    return utils.update_db_object(session, host_log_history, **kwargs)
+
+
+@utils.supported_filters(
+    ADDED_LOG_FIELDS,
+    optional_support_keys=UPDATED_LOG_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_LOG_FIELDS)
+def add_host_log_history(
+    host_id, exception_when_existing=False,
+    filename=None, user=None, session=None, **kwargs
+):
+    """add a host log history."""
+    host = _get_host(host_id, session=session)
+    return utils.add_db_object(
+        session, models.HostLogHistory, exception_when_existing,
+        host.id, filename, **kwargs
+    )
+
+
+@utils.supported_filters(optional_support_keys=['poweron'])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEPLOY_HOST
+)
+@utils.wrap_to_dict(
+    RESP_DEPLOY_FIELDS,
+    host=RESP_CONFIG_FIELDS
+)
+def poweron_host(
+    host_id, poweron={}, user=None, session=None, **kwargs
+):
+    """power on host."""
+    from compass.tasks import client as celery_client
+    host = _get_host(host_id, session=session)
+    check_host_validated(host)
+    if not user:
+        user_id = host.creator_id
+        user_dict = user_api.get_user(user_id, session=session)
+        user_email = user_dict['email']
+    else:
+        user_email = user.email
+    celery_client.celery.send_task(
+        'compass.tasks.poweron_host',
+        (host.id,),
+        queue=user_email,
+        exchange=user_email,
+        routing_key=user_email
+    )
+    return {
+        'status': 'poweron %s action sent' % host.name,
+        'host': host
+    }
+
+
+@utils.supported_filters(optional_support_keys=['poweroff'])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEPLOY_HOST
+)
+@utils.wrap_to_dict(
+    RESP_DEPLOY_FIELDS,
+    host=RESP_CONFIG_FIELDS
+)
+def poweroff_host(
+    host_id, poweroff={}, user=None, session=None, **kwargs
+):
+    """power off host."""
+    from compass.tasks import client as celery_client
+    host = _get_host(host_id, session=session)
+    check_host_validated(host)
+    if not user:
+        user_id = host.creator_id
+        user_dict = user_api.get_user(user_id, session=session)
+        user_email = user_dict['email']
+    else:
+        user_email = user.email
+    celery_client.celery.send_task(
+        'compass.tasks.poweroff_host',
+        (host.id,),
+        queue=user_email,
+        exchange=user_email,
+        routing_key=user_email
+    )
+    return {
+        'status': 'poweroff %s action sent' % host.name,
+        'host': host
+    }
+
+
+@utils.supported_filters(optional_support_keys=['reset'])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEPLOY_HOST
+)
+@utils.wrap_to_dict(
+    RESP_DEPLOY_FIELDS,
+    host=RESP_CONFIG_FIELDS
+)
+def reset_host(
+    host_id, reset={}, user=None, session=None, **kwargs
+):
+    """reset host."""
+    from compass.tasks import client as celery_client
+    host = _get_host(host_id, session=session)
+    check_host_validated(host)
+    if not user:
+        user_id = host.creator_id
+        user_dict = user_api.get_user(user_id, session=session)
+        user_email = user_dict['email']
+    else:
+        user_email = user.email
+    celery_client.celery.send_task(
+        'compass.tasks.reset_host',
+        (host.id,),
+        queue=user_email,
+        exchange=user_email,
+        routing_key=user_email
+    )
+    return {
+        'status': 'reset %s action sent' % host.name,
+        'host': host
+    }
diff --git a/compass-tasks/db/api/machine.py b/compass-tasks/db/api/machine.py
new file mode 100644
index 0000000..b7b16b2
--- /dev/null
+++ b/compass-tasks/db/api/machine.py
@@ -0,0 +1,317 @@
+# Copyright 2014 Huawei Technologies Co. Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Switch database operations."""
+import logging
+import re
+
+from compass.db.api import database
+from compass.db.api import permission
+from compass.db.api import user as user_api
+from compass.db.api import utils
+from compass.db import exception
+from compass.db import models
+
+from compass.utils import setting_wrapper as setting
+from compass.utils import util
+
+
+MACHINE_PRIMARY_FILEDS = ['mac', 'owner_id']
+SUPPORTED_FIELDS = [
+    'mac', 'tag', 'location',
+    'machine_attributes', 'owner_id']
+IGNORE_FIELDS = ['id', 'created_at', 'updated_at']
+UPDATED_FIELDS = [
+    'ipmi_credentials', 'machine_attributes',
+    'tag', 'location']
+PATCHED_FIELDS = [
+    'patched_ipmi_credentials', 'patched_tag',
+    'patched_location'
+]
+RESP_FIELDS = [
+    'id', 'mac', 'ipmi_credentials', 'switches', 'switch_ip',
+    'port', 'vlans', 'machine_attributes', 'owner_id',
+    'tag', 'location', 'created_at', 'updated_at'
+]
+RESP_DEPLOY_FIELDS = [
+    'status', 'machine'
+]
+
+
+def _get_machine(machine_id, session=None, **kwargs):
+    """Get machine by id."""
+    if isinstance(machine_id, (int, long)):
+        return utils.get_db_object(
+            session, models.Machine,
+            id=machine_id, **kwargs
+        )
+    raise exception.InvalidParameter(
+        'machine id %s type is not int compatible' % machine_id
+    )
+
+
+@utils.supported_filters(
+    MACHINE_PRIMARY_FILEDS,
+    optional_support_keys=SUPPORTED_FIELDS
+)
+@utils.input_validates(mac=utils.check_mac)
+def _add_machine(mac, owner_id=None, session=None, **kwargs):
+    """Add a machine."""
+    if isinstance(owner_id, (int, long)):
+        return utils.add_db_object(
+            session, models.Machine,
+            True,
+            mac,
+            owner_id=owner_id,
+            **kwargs
+        )
+    raise exception.InvalidParameter(
+        'owner id %s type is not int compatible' % owner_id
+    )
+
+
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_FIELDS)
+def add_machine(
+    mac, owner_id=None, session=None, user=None, **kwargs
+):
+    """Add a machine."""
+    return _add_machine(
+        mac,
+        owner_id=owner_id,
+        session=session, **kwargs
+    )
+
+
+def get_machine_internal(machine_id, session=None, **kwargs):
+    """Helper function to other files under db/api."""
+    return _get_machine(machine_id, session=session, **kwargs)
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_MACHINES
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def get_machine(
+    machine_id, exception_when_missing=True,
+    user=None, session=None, **kwargs
+):
+    """get a machine."""
+    return _get_machine(
+        machine_id, session=session,
+        exception_when_missing=exception_when_missing
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=SUPPORTED_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_MACHINES
+)
+@utils.output_filters(
+    tag=utils.general_filter_callback,
+    location=utils.general_filter_callback
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def list_machines(user=None, session=None, **filters):
+    """List machines."""
+    machines = utils.list_db_objects(
+        session, models.Machine, **filters
+    )
+    if not user.is_admin and len(machines):
+        machines = [m for m in machines if m.owner_id == user.id]
+    return machines
+
+
+@utils.wrap_to_dict(RESP_FIELDS)
+def _update_machine(machine_id, session=None, **kwargs):
+    """Update a machine."""
+    machine = _get_machine(machine_id, session=session)
+    return utils.update_db_object(session, machine, **kwargs)
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(ipmi_credentials=utils.check_ipmi_credentials)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_MACHINE
+)
+def update_machine(machine_id, user=None, session=None, **kwargs):
+    """Update a machine."""
+    return _update_machine(
+        machine_id, session=session, **kwargs
+    )
+
+
+# replace [ipmi_credentials, tag, location] to
+# [patched_ipmi_credentials, patched_tag, patched_location]
+# in kwargs. It tells db these fields will be patched.
+@utils.replace_filters(
+    ipmi_credentials='patched_ipmi_credentials',
+    tag='patched_tag',
+    location='patched_location'
+)
+@utils.supported_filters(
+    optional_support_keys=PATCHED_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@utils.output_validates(ipmi_credentials=utils.check_ipmi_credentials)
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_MACHINE
+)
+def patch_machine(machine_id, user=None, session=None, **kwargs):
+    """Patch a machine."""
+    return _update_machine(
+        machine_id, session=session, **kwargs
+    )
+
+
+def _check_machine_deletable(machine):
+    """Check a machine deletable."""
+    if machine.host:
+        host = machine.host
+        raise exception.NotAcceptable(
+            'machine %s has host %s on it' % (
+                machine.mac, host.name
+            )
+        )
+
+
+@utils.supported_filters()
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEL_MACHINE
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def del_machine(machine_id, user=None, session=None, **kwargs):
+    """Delete a machine."""
+    machine = _get_machine(machine_id, session=session)
+    _check_machine_deletable(machine)
+    return utils.del_db_object(session, machine)
+
+
+@utils.supported_filters(optional_support_keys=['poweron'])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEPLOY_HOST
+)
+@utils.wrap_to_dict(
+    RESP_DEPLOY_FIELDS,
+    machine=RESP_FIELDS
+)
+def poweron_machine(
+    machine_id, poweron={}, user=None, session=None, **kwargs
+):
+    """power on machine."""
+    from compass.tasks import client as celery_client
+    machine = _get_machine(
+        machine_id, session=session
+    )
+    if not user:
+        user_id = machine.owner_id
+        user_dict = user_api.get_user(user_id, session=session)
+        user_email = user_dict['email']
+    else:
+        user_email = user.email
+    celery_client.celery.send_task(
+        'compass.tasks.poweron_machine',
+        (machine_id,),
+        queue=user_email,
+        exchange=user_email,
+        routing_key=user_email
+    )
+    return {
+        'status': 'poweron %s action sent' % machine.mac,
+        'machine': machine
+    }
+
+
+@utils.supported_filters(optional_support_keys=['poweroff'])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEPLOY_HOST
+)
+@utils.wrap_to_dict(
+    RESP_DEPLOY_FIELDS,
+    machine=RESP_FIELDS
+)
+def poweroff_machine(
+    machine_id, poweroff={}, user=None, session=None, **kwargs
+):
+    """power off machine."""
+    from compass.tasks import client as celery_client
+    machine = _get_machine(
+        machine_id, session=session
+    )
+    if not user:
+        user_id = machine.owner_id
+        user_dict = user_api.get_user(user_id, session=session)
+        user_email = user_dict['email']
+    else:
+        user_email = user.email
+    celery_client.celery.send_task(
+        'compass.tasks.poweroff_machine',
+        (machine_id,),
+        queue=user_email,
+        exchange=user_email,
+        routing_key=user_email
+    )
+    return {
+        'status': 'poweroff %s action sent' % machine.mac,
+        'machine': machine
+    }
+
+
+@utils.supported_filters(optional_support_keys=['reset'])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEPLOY_HOST
+)
+@utils.wrap_to_dict(
+    RESP_DEPLOY_FIELDS,
+    machine=RESP_FIELDS
+)
+def reset_machine(
+    machine_id, reset={}, user=None, session=None, **kwargs
+):
+    """reset machine."""
+    from compass.tasks import client as celery_client
+    machine = _get_machine(
+        machine_id, session=session
+    )
+    if not user:
+        user_id = machine.owner_id
+        user_dict = user_api.get_user(user_id, session=session)
+        user_email = user_dict['email']
+    else:
+        user_email = user.email
+    celery_client.celery.send_task(
+        'compass.tasks.reset_machine',
+        (machine_id,),
+        queue=user_email,
+        exchange=user_email,
+        routing_key=user_email
+    )
+    return {
+        'status': 'reset %s action sent' % machine.mac,
+        'machine': machine
+    }
diff --git a/compass-tasks/db/api/metadata.py b/compass-tasks/db/api/metadata.py
new file mode 100644
index 0000000..16310c8
--- /dev/null
+++ b/compass-tasks/db/api/metadata.py
@@ -0,0 +1,517 @@
+# Copyright 2014 Huawei Technologies Co. Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Metadata related database operations."""
+import copy
+import logging
+import string
+
+from compass.db.api import adapter as adapter_api
+from compass.db.api import database
+from compass.db.api import utils
+from compass.db import callback as metadata_callback
+from compass.db import exception
+from compass.db import models
+from compass.db import validator as metadata_validator
+
+
+from compass.utils import setting_wrapper as setting
+from compass.utils import util
+
+
+OS_FIELDS = None
+PACKAGE_FIELDS = None
+FLAVOR_FIELDS = None
+OSES_METADATA = None
+PACKAGES_METADATA = None
+FLAVORS_METADATA = None
+OSES_METADATA_UI_CONVERTERS = None
+FLAVORS_METADATA_UI_CONVERTERS = None
+
+
+def _get_field_from_configuration(configs):
+    """Get fields from configurations."""
+    fields = {}
+    for config in configs:
+        if not isinstance(config, dict):
+            raise exception.InvalidParameter(
+                'config %s is not dict' % config
+            )
+        field_name = config['NAME']
+        fields[field_name] = {
+            'name': field_name,
+            'id': field_name,
+            'field_type': config.get('FIELD_TYPE', basestring),
+            'display_type': config.get('DISPLAY_TYPE', 'text'),
+            'validator': config.get('VALIDATOR', None),
+            'js_validator': config.get('JS_VALIDATOR', None),
+            'description': config.get('DESCRIPTION', field_name)
+        }
+    return fields
+
+
+def _get_os_fields_from_configuration():
+    """Get os fields from os field config dir."""
+    env_locals = {}
+    env_locals.update(metadata_validator.VALIDATOR_LOCALS)
+    env_locals.update(metadata_callback.CALLBACK_LOCALS)
+    configs = util.load_configs(
+        setting.OS_FIELD_DIR,
+        env_locals=env_locals
+    )
+    return _get_field_from_configuration(
+        configs
+    )
+
+
+def _get_package_fields_from_configuration():
+    """Get package fields from package field config dir."""
+    env_locals = {}
+    env_locals.update(metadata_validator.VALIDATOR_LOCALS)
+    env_locals.update(metadata_callback.CALLBACK_LOCALS)
+    configs = util.load_configs(
+        setting.PACKAGE_FIELD_DIR,
+        env_locals=env_locals
+    )
+    return _get_field_from_configuration(
+        configs
+    )
+
+
+def _get_flavor_fields_from_configuration():
+    """Get flavor fields from flavor field config dir."""
+    env_locals = {}
+    env_locals.update(metadata_validator.VALIDATOR_LOCALS)
+    env_locals.update(metadata_callback.CALLBACK_LOCALS)
+    configs = util.load_configs(
+        setting.FLAVOR_FIELD_DIR,
+        env_locals=env_locals
+    )
+    return _get_field_from_configuration(
+        configs
+    )
+
+
+def _get_metadata_from_configuration(
+    path, name, config,
+    fields, **kwargs
+):
+    """Recursively get metadata from configuration.
+
+    Args:
+       path: used to indicate the path to the root element.
+             mainly for trouble shooting.
+       name: the key of the metadata section.
+       config: the value of the metadata section.
+       fields: all fields defined in os fields or package fields dir.
+    """
+    if not isinstance(config, dict):
+        raise exception.InvalidParameter(
+            '%s config %s is not dict' % (path, config)
+        )
+    metadata_self = config.get('_self', {})
+    if 'field' in metadata_self:
+        field_name = metadata_self['field']
+        field = fields[field_name]
+    else:
+        field = {}
+    # mapping to may contain $ like $partition. Here we replace the
+    # $partition to the key of the correspendent config. The backend then
+    # can use this kind of feature to support multi partitions when we
+    # only declare the partition metadata in one place.
+    mapping_to_template = metadata_self.get('mapping_to', None)
+    if mapping_to_template:
+        mapping_to = string.Template(
+            mapping_to_template
+        ).safe_substitute(
+            **kwargs
+        )
+    else:
+        mapping_to = None
+    self_metadata = {
+        'name': name,
+        'display_name': metadata_self.get('display_name', name),
+        'field_type': field.get('field_type', dict),
+        'display_type': field.get('display_type', None),
+        'description': metadata_self.get(
+            'description', field.get('description', None)
+        ),
+        'is_required': metadata_self.get('is_required', False),
+        'required_in_whole_config': metadata_self.get(
+            'required_in_whole_config', False),
+        'mapping_to': mapping_to,
+        'validator': metadata_self.get(
+            'validator', field.get('validator', None)
+        ),
+        'js_validator': metadata_self.get(
+            'js_validator', field.get('js_validator', None)
+        ),
+        'default_value': metadata_self.get('default_value', None),
+        'default_callback': metadata_self.get('default_callback', None),
+        'default_callback_params': metadata_self.get(
+            'default_callback_params', {}),
+        'options': metadata_self.get('options', None),
+        'options_callback': metadata_self.get('options_callback', None),
+        'options_callback_params': metadata_self.get(
+            'options_callback_params', {}),
+        'autofill_callback': metadata_self.get(
+            'autofill_callback', None),
+        'autofill_callback_params': metadata_self.get(
+            'autofill_callback_params', {}),
+        'required_in_options': metadata_self.get(
+            'required_in_options', False)
+    }
+    self_metadata.update(kwargs)
+    metadata = {'_self': self_metadata}
+    # Key extension used to do two things:
+    # one is to return the extended metadata that $<something>
+    # will be replace to possible extensions.
+    # The other is to record the $<something> to extended value
+    # and used in future mapping_to subsititution.
+    # TODO(grace): select proper name instead of key_extensions if
+    # you think it is better.
+    # Suppose key_extension is {'$partition': ['/var', '/']} for $partition
+    # the metadata for $partition will be mapped to {
+    # '/var': ..., '/': ...} and kwargs={'partition': '/var'} and
+    # kwargs={'partition': '/'} will be parsed to recursive metadata parsing
+    # for sub metadata under '/var' and '/'. Then in the metadata parsing
+    # for the sub metadata, this kwargs will be used to substitute mapping_to.
+    key_extensions = metadata_self.get('key_extensions', {})
+    general_keys = []
+    for key, value in config.items():
+        if key.startswith('_'):
+            continue
+        if key in key_extensions:
+            if not key.startswith('$'):
+                raise exception.InvalidParameter(
+                    '%s subkey %s should start with $' % (
+                        path, key
+                    )
+                )
+            extended_keys = key_extensions[key]
+            for extended_key in extended_keys:
+                if extended_key.startswith('$'):
+                    raise exception.InvalidParameter(
+                        '%s extended key %s should not start with $' % (
+                            path, extended_key
+                        )
+                    )
+                sub_kwargs = dict(kwargs)
+                sub_kwargs[key[1:]] = extended_key
+                metadata[extended_key] = _get_metadata_from_configuration(
+                    '%s/%s' % (path, extended_key), extended_key, value,
+                    fields, **sub_kwargs
+                )
+        else:
+            if key.startswith('$'):
+                general_keys.append(key)
+            metadata[key] = _get_metadata_from_configuration(
+                '%s/%s' % (path, key), key, value,
+                fields, **kwargs
+            )
+        if len(general_keys) > 1:
+            raise exception.InvalidParameter(
+                'foud multi general keys in %s: %s' % (
+                    path, general_keys
+                )
+            )
+    return metadata
+
+
+def _get_oses_metadata_from_configuration():
+    """Get os metadata from os metadata config dir."""
+    oses_metadata = {}
+    env_locals = {}
+    env_locals.update(metadata_validator.VALIDATOR_LOCALS)
+    env_locals.update(metadata_callback.CALLBACK_LOCALS)
+    configs = util.load_configs(
+        setting.OS_METADATA_DIR,
+        env_locals=env_locals
+    )
+    for config in configs:
+        os_name = config['OS']
+        os_metadata = oses_metadata.setdefault(os_name, {})
+        for key, value in config['METADATA'].items():
+            os_metadata[key] = _get_metadata_from_configuration(
+                key, key, value, OS_FIELDS
+            )
+
+    oses = adapter_api.OSES
+    parents = {}
+    for os_name, os in oses.items():
+        parent = os.get('parent', None)
+        parents[os_name] = parent
+    for os_name, os in oses.items():
+        oses_metadata[os_name] = util.recursive_merge_dict(
+            os_name, oses_metadata, parents
+        )
+    return oses_metadata
+
+
+def _get_packages_metadata_from_configuration():
+    """Get package metadata from package metadata config dir."""
+    packages_metadata = {}
+    env_locals = {}
+    env_locals.update(metadata_validator.VALIDATOR_LOCALS)
+    env_locals.update(metadata_callback.CALLBACK_LOCALS)
+    configs = util.load_configs(
+        setting.PACKAGE_METADATA_DIR,
+        env_locals=env_locals
+    )
+    for config in configs:
+        adapter_name = config['ADAPTER']
+        package_metadata = packages_metadata.setdefault(adapter_name, {})
+        for key, value in config['METADATA'].items():
+            package_metadata[key] = _get_metadata_from_configuration(
+                key, key, value, PACKAGE_FIELDS
+            )
+    adapters = adapter_api.ADAPTERS
+    parents = {}
+    for adapter_name, adapter in adapters.items():
+        parent = adapter.get('parent', None)
+        parents[adapter_name] = parent
+    for adapter_name, adapter in adapters.items():
+        packages_metadata[adapter_name] = util.recursive_merge_dict(
+            adapter_name, packages_metadata, parents
+        )
+    return packages_metadata
+
+
+def _get_flavors_metadata_from_configuration():
+    """Get flavor metadata from flavor metadata config dir."""
+    flavors_metadata = {}
+    env_locals = {}
+    env_locals.update(metadata_validator.VALIDATOR_LOCALS)
+    env_locals.update(metadata_callback.CALLBACK_LOCALS)
+    configs = util.load_configs(
+        setting.FLAVOR_METADATA_DIR,
+        env_locals=env_locals
+    )
+    for config in configs:
+        adapter_name = config['ADAPTER']
+        flavor_name = config['FLAVOR']
+        flavor_metadata = flavors_metadata.setdefault(
+            adapter_name, {}
+        ).setdefault(flavor_name, {})
+        for key, value in config['METADATA'].items():
+            flavor_metadata[key] = _get_metadata_from_configuration(
+                key, key, value, FLAVOR_FIELDS
+            )
+
+    packages_metadata = PACKAGES_METADATA
+    adapters_flavors = adapter_api.ADAPTERS_FLAVORS
+    for adapter_name, adapter_flavors in adapters_flavors.items():
+        package_metadata = packages_metadata.get(adapter_name, {})
+        for flavor_name, flavor in adapter_flavors.items():
+            flavor_metadata = flavors_metadata.setdefault(
+                adapter_name, {}
+            ).setdefault(flavor_name, {})
+            util.merge_dict(flavor_metadata, package_metadata, override=False)
+    return flavors_metadata
+
+
+def _filter_metadata(metadata, **kwargs):
+    if not isinstance(metadata, dict):
+        return metadata
+    filtered_metadata = {}
+    for key, value in metadata.items():
+        if key == '_self':
+            default_value = value.get('default_value', None)
+            if default_value is None:
+                default_callback_params = value.get(
+                    'default_callback_params', {}
+                )
+                callback_params = dict(kwargs)
+                if default_callback_params:
+                    callback_params.update(default_callback_params)
+                default_callback = value.get('default_callback', None)
+                if default_callback:
+                    default_value = default_callback(key, **callback_params)
+            options = value.get('options', None)
+            if options is None:
+                options_callback_params = value.get(
+                    'options_callback_params', {}
+                )
+                callback_params = dict(kwargs)
+                if options_callback_params:
+                    callback_params.update(options_callback_params)
+
+                options_callback = value.get('options_callback', None)
+                if options_callback:
+                    options = options_callback(key, **callback_params)
+            filtered_metadata[key] = value
+            if default_value is not None:
+                filtered_metadata[key]['default_value'] = default_value
+            if options is not None:
+                filtered_metadata[key]['options'] = options
+        else:
+            filtered_metadata[key] = _filter_metadata(value, **kwargs)
+    return filtered_metadata
+
+
+def _load_metadata(force_reload=False):
+    """Load metadata information into memory.
+
+    If force_reload, the metadata information will be reloaded
+    even if the metadata is already loaded.
+    """
+    adapter_api.load_adapters_internal(force_reload=force_reload)
+    global OS_FIELDS
+    if force_reload or OS_FIELDS is None:
+        OS_FIELDS = _get_os_fields_from_configuration()
+    global PACKAGE_FIELDS
+    if force_reload or PACKAGE_FIELDS is None:
+        PACKAGE_FIELDS = _get_package_fields_from_configuration()
+    global FLAVOR_FIELDS
+    if force_reload or FLAVOR_FIELDS is None:
+        FLAVOR_FIELDS = _get_flavor_fields_from_configuration()
+    global OSES_METADATA
+    if force_reload or OSES_METADATA is None:
+        OSES_METADATA = _get_oses_metadata_from_configuration()
+    global PACKAGES_METADATA
+    if force_reload or PACKAGES_METADATA is None:
+        PACKAGES_METADATA = _get_packages_metadata_from_configuration()
+    global FLAVORS_METADATA
+    if force_reload or FLAVORS_METADATA is None:
+        FLAVORS_METADATA = _get_flavors_metadata_from_configuration()
+    global OSES_METADATA_UI_CONVERTERS
+    if force_reload or OSES_METADATA_UI_CONVERTERS is None:
+        OSES_METADATA_UI_CONVERTERS = (
+            _get_oses_metadata_ui_converters_from_configuration()
+        )
+    global FLAVORS_METADATA_UI_CONVERTERS
+    if force_reload or FLAVORS_METADATA_UI_CONVERTERS is None:
+        FLAVORS_METADATA_UI_CONVERTERS = (
+            _get_flavors_metadata_ui_converters_from_configuration()
+        )
+
+
+def _get_oses_metadata_ui_converters_from_configuration():
+    """Get os metadata ui converters from os metadata mapping config dir.
+
+    os metadata ui converter is used to convert os metadata to
+    the format UI can understand and show.
+    """
+    oses_metadata_ui_converters = {}
+    configs = util.load_configs(setting.OS_MAPPING_DIR)
+    for config in configs:
+        os_name = config['OS']
+        oses_metadata_ui_converters[os_name] = config.get('CONFIG_MAPPING', {})
+
+    oses = adapter_api.OSES
+    parents = {}
+    for os_name, os in oses.items():
+        parent = os.get('parent', None)
+        parents[os_name] = parent
+    for os_name, os in oses.items():
+        oses_metadata_ui_converters[os_name] = util.recursive_merge_dict(
+            os_name, oses_metadata_ui_converters, parents
+        )
+    return oses_metadata_ui_converters
+
+
+def _get_flavors_metadata_ui_converters_from_configuration():
+    """Get flavor metadata ui converters from flavor mapping config dir."""
+    flavors_metadata_ui_converters = {}
+    configs = util.load_configs(setting.FLAVOR_MAPPING_DIR)
+    for config in configs:
+        adapter_name = config['ADAPTER']
+        flavor_name = config['FLAVOR']
+        flavors_metadata_ui_converters.setdefault(
+            adapter_name, {}
+        )[flavor_name] = config.get('CONFIG_MAPPING', {})
+    adapters = adapter_api.ADAPTERS
+    parents = {}
+    for adapter_name, adapter in adapters.items():
+        parent = adapter.get('parent', None)
+        parents[adapter_name] = parent
+    for adapter_name, adapter in adapters.items():
+        flavors_metadata_ui_converters[adapter_name] = (
+            util.recursive_merge_dict(
+                adapter_name, flavors_metadata_ui_converters, parents
+            )
+        )
+    return flavors_metadata_ui_converters
+
+
+def get_packages_metadata_internal(force_reload=False):
+    """Get deployable package metadata."""
+    _load_metadata(force_reload=force_reload)
+    metadata_mapping = {}
+    adapters = adapter_api.ADAPTERS
+    for adapter_name, adapter in adapters.items():
+        if adapter.get('deployable'):
+            metadata_mapping[adapter_name] = _filter_metadata(
+                PACKAGES_METADATA.get(adapter_name, {})
+            )
+        else:
+            logging.info(
+                'ignore metadata since its adapter %s is not deployable',
+                adapter_name
+            )
+    return metadata_mapping
+
+
+def get_flavors_metadata_internal(force_reload=False):
+    """Get deployable flavor metadata."""
+    _load_metadata(force_reload=force_reload)
+    metadata_mapping = {}
+    adapters_flavors = adapter_api.ADAPTERS_FLAVORS
+    for adapter_name, adapter_flavors in adapters_flavors.items():
+        adapter = adapter_api.ADAPTERS[adapter_name]
+        if not adapter.get('deployable'):
+            logging.info(
+                'ignore metadata since its adapter %s is not deployable',
+                adapter_name
+            )
+            continue
+        for flavor_name, flavor in adapter_flavors.items():
+            flavor_metadata = FLAVORS_METADATA.get(
+                adapter_name, {}
+            ).get(flavor_name, {})
+            metadata = _filter_metadata(flavor_metadata)
+            metadata_mapping.setdefault(
+                adapter_name, {}
+            )[flavor_name] = metadata
+    return metadata_mapping
+
+
+def get_flavors_metadata_ui_converters_internal(force_reload=False):
+    """Get usable flavor metadata ui converters."""
+    _load_metadata(force_reload=force_reload)
+    return FLAVORS_METADATA_UI_CONVERTERS
+
+
+def get_oses_metadata_internal(force_reload=False):
+    """Get deployable os metadata."""
+    _load_metadata(force_reload=force_reload)
+    metadata_mapping = {}
+    oses = adapter_api.OSES
+    for os_name, os in oses.items():
+        if os.get('deployable'):
+            metadata_mapping[os_name] = _filter_metadata(
+                OSES_METADATA.get(os_name, {})
+            )
+        else:
+            logging.info(
+                'ignore metadata since its os %s is not deployable',
+                os_name
+            )
+    return metadata_mapping
+
+
+def get_oses_metadata_ui_converters_internal(force_reload=False):
+    """Get usable os metadata ui converters."""
+    _load_metadata(force_reload=force_reload)
+    return OSES_METADATA_UI_CONVERTERS
diff --git a/compass-tasks/db/api/metadata_holder.py b/compass-tasks/db/api/metadata_holder.py
new file mode 100644
index 0000000..24afc67
--- /dev/null
+++ b/compass-tasks/db/api/metadata_holder.py
@@ -0,0 +1,731 @@
+# Copyright 2014 Huawei Technologies Co. Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Metadata related object holder."""
+import logging
+
+from compass.db.api import adapter as adapter_api
+from compass.db.api import adapter_holder as adapter_holder_api
+from compass.db.api import database
+from compass.db.api import metadata as metadata_api
+from compass.db.api import permission
+from compass.db.api import user as user_api
+from compass.db.api import utils
+from compass.db import exception
+from compass.db import models
+from compass.utils import setting_wrapper as setting
+from compass.utils import util
+
+
+RESP_METADATA_FIELDS = [
+    'os_config', 'package_config'
+]
+RESP_UI_METADATA_FIELDS = [
+    'os_global_config', 'flavor_config'
+]
+
+
+def load_metadatas(force_reload=False):
+    """Load metadatas."""
+    # TODO(xicheng): today we load metadata in memory as it original
+    # format in files in metadata.py. We get these inmemory metadata
+    # and do some translation, store the translated metadata into memory
+    # too in metadata_holder.py. api can only access the global inmemory
+    # data in metadata_holder.py.
+    _load_os_metadatas(force_reload=force_reload)
+    _load_package_metadatas(force_reload=force_reload)
+    _load_flavor_metadatas(force_reload=force_reload)
+    _load_os_metadata_ui_converters(force_reload=force_reload)
+    _load_flavor_metadata_ui_converters(force_reload=force_reload)
+
+
+def _load_os_metadata_ui_converters(force_reload=False):
+    global OS_METADATA_UI_CONVERTERS
+    if force_reload or OS_METADATA_UI_CONVERTERS is None:
+        logging.info('load os metadatas ui converters into memory')
+        OS_METADATA_UI_CONVERTERS = (
+            metadata_api.get_oses_metadata_ui_converters_internal(
+                force_reload=force_reload
+            )
+        )
+
+
+def _load_os_metadatas(force_reload=False):
+    """Load os metadata from inmemory db and map it by os_id."""
+    global OS_METADATA_MAPPING
+    if force_reload or OS_METADATA_MAPPING is None:
+        logging.info('load os metadatas into memory')
+        OS_METADATA_MAPPING = metadata_api.get_oses_metadata_internal(
+            force_reload=force_reload
+        )
+
+
+def _load_flavor_metadata_ui_converters(force_reload=False):
+    """Load flavor metadata ui converters from inmemory db.
+
+    The loaded metadata is mapped by flavor id.
+    """
+    global FLAVOR_METADATA_UI_CONVERTERS
+    if force_reload or FLAVOR_METADATA_UI_CONVERTERS is None:
+        logging.info('load flavor metadata ui converters into memory')
+        FLAVOR_METADATA_UI_CONVERTERS = {}
+        adapters_flavors_metadata_ui_converters = (
+            metadata_api.get_flavors_metadata_ui_converters_internal(
+                force_reload=force_reload
+            )
+        )
+        for adapter_name, adapter_flavors_metadata_ui_converters in (
+            adapters_flavors_metadata_ui_converters.items()
+        ):
+            for flavor_name, flavor_metadata_ui_converter in (
+                adapter_flavors_metadata_ui_converters.items()
+            ):
+                FLAVOR_METADATA_UI_CONVERTERS[
+                    '%s:%s' % (adapter_name, flavor_name)
+                ] = flavor_metadata_ui_converter
+
+
+@util.deprecated
+def _load_package_metadatas(force_reload=False):
+    """Load deployable package metadata from inmemory db."""
+    global PACKAGE_METADATA_MAPPING
+    if force_reload or PACKAGE_METADATA_MAPPING is None:
+        logging.info('load package metadatas into memory')
+        PACKAGE_METADATA_MAPPING = (
+            metadata_api.get_packages_metadata_internal(
+                force_reload=force_reload
+            )
+        )
+
+
+def _load_flavor_metadatas(force_reload=False):
+    """Load flavor metadata from inmemory db.
+
+    The loaded metadata are mapped by flavor id.
+    """
+    global FLAVOR_METADATA_MAPPING
+    if force_reload or FLAVOR_METADATA_MAPPING is None:
+        logging.info('load flavor metadatas into memory')
+        FLAVOR_METADATA_MAPPING = {}
+        adapters_flavors_metadata = (
+            metadata_api.get_flavors_metadata_internal(
+                force_reload=force_reload
+            )
+        )
+        for adapter_name, adapter_flavors_metadata in (
+            adapters_flavors_metadata.items()
+        ):
+            for flavor_name, flavor_metadata in (
+                adapter_flavors_metadata.items()
+            ):
+                FLAVOR_METADATA_MAPPING[
+                    '%s:%s' % (adapter_name, flavor_name)
+                ] = flavor_metadata
+
+
+OS_METADATA_MAPPING = None
+PACKAGE_METADATA_MAPPING = None
+FLAVOR_METADATA_MAPPING = None
+OS_METADATA_UI_CONVERTERS = None
+FLAVOR_METADATA_UI_CONVERTERS = None
+
+
+def validate_os_config(
+    config, os_id, whole_check=False, **kwargs
+):
+    """Validate os config."""
+    load_metadatas()
+    if os_id not in OS_METADATA_MAPPING:
+        raise exception.InvalidParameter(
+            'os %s is not found in os metadata mapping' % os_id
+        )
+    _validate_config(
+        '', config, OS_METADATA_MAPPING[os_id],
+        whole_check, **kwargs
+    )
+
+
+@util.deprecated
+def validate_package_config(
+    config, adapter_id, whole_check=False, **kwargs
+):
+    """Validate package config."""
+    load_metadatas()
+    if adapter_id not in PACKAGE_METADATA_MAPPING:
+        raise exception.InvalidParameter(
+            'adapter %s is not found in package metedata mapping' % adapter_id
+        )
+    _validate_config(
+        '', config, PACKAGE_METADATA_MAPPING[adapter_id],
+        whole_check, **kwargs
+    )
+
+
+def validate_flavor_config(
+    config, flavor_id, whole_check=False, **kwargs
+):
+    """Validate flavor config."""
+    load_metadatas()
+    if not flavor_id:
+        logging.info('There is no flavor, skipping flavor validation...')
+    elif flavor_id not in FLAVOR_METADATA_MAPPING:
+        raise exception.InvalidParameter(
+            'flavor %s is not found in flavor metedata mapping' % flavor_id
+        )
+    else:
+        _validate_config(
+            '', config, FLAVOR_METADATA_MAPPING[flavor_id],
+            whole_check, **kwargs
+        )
+
+
+def _filter_metadata(metadata, **kwargs):
+    """Filter metadata before return it to api.
+
+    Some metadata fields are not json compatible or
+    only used in db/api internally.
+    We should strip these fields out before return to api.
+    """
+    if not isinstance(metadata, dict):
+        return metadata
+    filtered_metadata = {}
+    for key, value in metadata.items():
+        if key == '_self':
+            filtered_metadata[key] = {
+                'name': value['name'],
+                'description': value.get('description', None),
+                'default_value': value.get('default_value', None),
+                'is_required': value.get('is_required', False),
+                'required_in_whole_config': value.get(
+                    'required_in_whole_config', False),
+                'js_validator': value.get('js_validator', None),
+                'options': value.get('options', None),
+                'required_in_options': value.get(
+                    'required_in_options', False),
+                'field_type': value.get(
+                    'field_type_data', 'str'),
+                'display_type': value.get('display_type', None),
+                'mapping_to': value.get('mapping_to', None)
+            }
+        else:
+            filtered_metadata[key] = _filter_metadata(value, **kwargs)
+    return filtered_metadata
+
+
+@util.deprecated
+def _get_package_metadata(adapter_id):
+    """get package metadata."""
+    load_metadatas()
+    if adapter_id not in PACKAGE_METADATA_MAPPING:
+        raise exception.RecordNotExists(
+            'adpater %s does not exist' % adapter_id
+        )
+    return _filter_metadata(
+        PACKAGE_METADATA_MAPPING[adapter_id]
+    )
+
+
+@util.deprecated
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_METADATAS
+)
+@utils.wrap_to_dict(RESP_METADATA_FIELDS)
+def get_package_metadata(adapter_id, user=None, session=None, **kwargs):
+    """Get package metadata from adapter."""
+    return {
+        'package_config': _get_package_metadata(adapter_id)
+    }
+
+
+def _get_flavor_metadata(flavor_id):
+    """get flavor metadata."""
+    load_metadatas()
+    if not flavor_id:
+        logging.info('There is no flavor id, skipping...')
+    elif flavor_id not in FLAVOR_METADATA_MAPPING:
+        raise exception.RecordNotExists(
+            'flavor %s does not exist' % flavor_id
+        )
+    else:
+        return _filter_metadata(FLAVOR_METADATA_MAPPING[flavor_id])
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_METADATAS
+)
+@utils.wrap_to_dict(RESP_METADATA_FIELDS)
+def get_flavor_metadata(flavor_id, user=None, session=None, **kwargs):
+    """Get flavor metadata by flavor."""
+    return {
+        'package_config': _get_flavor_metadata(flavor_id)
+    }
+
+
+def _get_os_metadata(os_id):
+    """get os metadata."""
+    load_metadatas()
+    if os_id not in OS_METADATA_MAPPING:
+        raise exception.RecordNotExists(
+            'os %s does not exist' % os_id
+        )
+    return _filter_metadata(OS_METADATA_MAPPING[os_id])
+
+
+def _get_os_metadata_ui_converter(os_id):
+    """get os metadata ui converter."""
+    load_metadatas()
+    if os_id not in OS_METADATA_UI_CONVERTERS:
+        raise exception.RecordNotExists(
+            'os %s does not exist' % os_id
+        )
+    return OS_METADATA_UI_CONVERTERS[os_id]
+
+
+def _get_flavor_metadata_ui_converter(flavor_id):
+    """get flavor metadata ui converter."""
+    load_metadatas()
+    if flavor_id not in FLAVOR_METADATA_UI_CONVERTERS:
+        raise exception.RecordNotExists(
+            'flavor %s does not exist' % flavor_id
+        )
+    return FLAVOR_METADATA_UI_CONVERTERS[flavor_id]
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_METADATAS
+)
+@utils.wrap_to_dict(RESP_METADATA_FIELDS)
+def get_os_metadata(os_id, user=None, session=None, **kwargs):
+    """get os metadatas."""
+    return {'os_config': _get_os_metadata(os_id)}
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_METADATAS
+)
+@utils.wrap_to_dict(RESP_UI_METADATA_FIELDS)
+def get_os_ui_metadata(os_id, user=None, session=None, **kwargs):
+    """Get os metadata ui converter by os."""
+    metadata = _get_os_metadata(os_id)
+    metadata_ui_converter = _get_os_metadata_ui_converter(os_id)
+    return _get_ui_metadata(metadata, metadata_ui_converter)
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_METADATAS
+)
+@utils.wrap_to_dict(RESP_UI_METADATA_FIELDS)
+def get_flavor_ui_metadata(flavor_id, user=None, session=None, **kwargs):
+    """Get flavor ui metadata by flavor."""
+    metadata = _get_flavor_metadata(flavor_id)
+    metadata_ui_converter = _get_flavor_metadata_ui_converter(flavor_id)
+    return _get_ui_metadata(metadata, metadata_ui_converter)
+
+
+def _get_ui_metadata(metadata, metadata_ui_converter):
+    """convert metadata to ui metadata.
+
+     Args:
+        metadata: metadata we defined in metadata files.
+        metadata_ui_converter: metadata ui converter defined in metadata
+                               mapping files. Used to convert orignal
+                               metadata to ui understandable metadata.
+
+     Returns:
+        ui understandable metadata.
+     """
+    ui_metadata = {}
+    ui_metadata[metadata_ui_converter['mapped_name']] = []
+    for mapped_child in metadata_ui_converter['mapped_children']:
+        data_dict = {}
+        for ui_key, ui_value in mapped_child.items():
+            for key, value in ui_value.items():
+                if 'data' == key:
+                    result_data = []
+                    _get_ui_metadata_data(
+                        metadata[ui_key], value, result_data
+                    )
+                    data_dict['data'] = result_data
+                else:
+                    data_dict[key] = value
+        ui_metadata[metadata_ui_converter['mapped_name']].append(data_dict)
+    return ui_metadata
+
+
+def _get_ui_metadata_data(metadata, config, result_data):
+    """Get ui metadata data and fill to result."""
+    data_dict = {}
+    for key, config_value in config.items():
+        if isinstance(config_value, dict) and key != 'content_data':
+            if key in metadata.keys():
+                _get_ui_metadata_data(metadata[key], config_value, result_data)
+            else:
+                _get_ui_metadata_data(metadata, config_value, result_data)
+        elif isinstance(config_value, list):
+            option_list = []
+            for item in config_value:
+                if isinstance(item, dict):
+                    option_list.append(item)
+                    data_dict[key] = option_list
+                else:
+                    if isinstance(metadata['_self'][item], bool):
+                        data_dict[item] = str(metadata['_self'][item]).lower()
+                    else:
+                        data_dict[item] = metadata['_self'][item]
+        else:
+            data_dict[key] = config_value
+    if data_dict:
+        result_data.append(data_dict)
+    return result_data
+
+
+@util.deprecated
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_METADATAS
+)
+@utils.wrap_to_dict(RESP_METADATA_FIELDS)
+def get_package_os_metadata(
+    adapter_id, os_id,
+    user=None, session=None, **kwargs
+):
+    """Get metadata by adapter and os."""
+    adapter = adapter_holder_api.get_adapter(
+        adapter_id, user=user, session=session
+    )
+    os_ids = [os['id'] for os in adapter['supported_oses']]
+    if os_id not in os_ids:
+        raise exception.InvalidParameter(
+            'os %s is not in the supported os list of adapter %s' % (
+                os_id, adapter_id
+            )
+        )
+    metadatas = {}
+    metadatas['os_config'] = _get_os_metadata(
+        os_id
+    )
+    metadatas['package_config'] = _get_package_metadata(
+        adapter_id
+    )
+    return metadatas
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_METADATAS
+)
+@utils.wrap_to_dict(RESP_METADATA_FIELDS)
+def get_flavor_os_metadata(
+    flavor_id, os_id,
+    user=None, session=None, **kwargs
+):
+    """Get metadata by flavor and os."""
+    flavor = adapter_holder_api.get_flavor(
+        flavor_id, user=user, session=session
+    )
+    adapter_id = flavor['adapter_id']
+    adapter = adapter_holder_api.get_adapter(
+        adapter_id, user=user, session=session
+    )
+    os_ids = [os['id'] for os in adapter['supported_oses']]
+    if os_id not in os_ids:
+        raise exception.InvalidParameter(
+            'os %s is not in the supported os list of adapter %s' % (
+                os_id, adapter_id
+            )
+        )
+    metadatas = {}
+    metadatas['os_config'] = _get_os_metadata(
+        session, os_id
+    )
+    metadatas['package_config'] = _get_flavor_metadata(
+        session, flavor_id
+    )
+    return metadatas
+
+
+def _validate_self(
+    config_path, config_key, config,
+    metadata, whole_check,
+    **kwargs
+):
+    """validate config by metadata self section."""
+    logging.debug('validate config self %s', config_path)
+    if '_self' not in metadata:
+        if isinstance(config, dict):
+            _validate_config(
+                config_path, config, metadata, whole_check, **kwargs
+            )
+        return
+    field_type = metadata['_self'].get('field_type', basestring)
+    if not isinstance(config, field_type):
+        raise exception.InvalidParameter(
+            '%s config type is not %s: %s' % (config_path, field_type, config)
+        )
+    is_required = metadata['_self'].get(
+        'is_required', False
+    )
+    required_in_whole_config = metadata['_self'].get(
+        'required_in_whole_config', False
+    )
+    if isinstance(config, basestring):
+        if config == '' and not is_required and not required_in_whole_config:
+            # ignore empty config when it is optional
+            return
+    required_in_options = metadata['_self'].get(
+        'required_in_options', False
+    )
+    options = metadata['_self'].get('options', None)
+    if required_in_options:
+        if field_type in [int, basestring, float, bool]:
+            if options and config not in options:
+                raise exception.InvalidParameter(
+                    '%s config is not in %s: %s' % (
+                        config_path, options, config
+                    )
+                )
+        elif field_type in [list, tuple]:
+            if options and not set(config).issubset(set(options)):
+                raise exception.InvalidParameter(
+                    '%s config is not in %s: %s' % (
+                        config_path, options, config
+                    )
+                )
+        elif field_type == dict:
+            if options and not set(config.keys()).issubset(set(options)):
+                raise exception.InvalidParameter(
+                    '%s config is not in %s: %s' % (
+                        config_path, options, config
+                    )
+                )
+    validator = metadata['_self'].get('validator', None)
+    logging.debug('validate by validator %s', validator)
+    if validator:
+        if not validator(config_key, config, **kwargs):
+            raise exception.InvalidParameter(
+                '%s config is invalid' % config_path
+            )
+    if isinstance(config, dict):
+        _validate_config(
+            config_path, config, metadata, whole_check, **kwargs
+        )
+
+
+def _validate_config(
+    config_path, config, metadata, whole_check,
+    **kwargs
+):
+    """validate config by metadata."""
+    logging.debug('validate config %s', config_path)
+    generals = {}
+    specified = {}
+    for key, value in metadata.items():
+        if key.startswith('$'):
+            generals[key] = value
+        elif key.startswith('_'):
+            pass
+        else:
+            specified[key] = value
+    config_keys = set(config.keys())
+    specified_keys = set(specified.keys())
+    intersect_keys = config_keys & specified_keys
+    not_found_keys = config_keys - specified_keys
+    redundant_keys = specified_keys - config_keys
+    for key in redundant_keys:
+        if '_self' not in specified[key]:
+            continue
+        if specified[key]['_self'].get('is_required', False):
+            raise exception.InvalidParameter(
+                '%s/%s does not find but it is required' % (
+                    config_path, key
+                )
+            )
+        if (
+            whole_check and
+            specified[key]['_self'].get(
+                'required_in_whole_config', False
+            )
+        ):
+            raise exception.InvalidParameter(
+                '%s/%s does not find but it is required in whole config' % (
+                    config_path, key
+                )
+            )
+    for key in intersect_keys:
+        _validate_self(
+            '%s/%s' % (config_path, key),
+            key, config[key], specified[key], whole_check,
+            **kwargs
+        )
+    for key in not_found_keys:
+        if not generals:
+            raise exception.InvalidParameter(
+                'key %s missing in metadata %s' % (
+                    key, config_path
+                )
+            )
+        for general_key, general_value in generals.items():
+            _validate_self(
+                '%s/%s' % (config_path, key),
+                key, config[key], general_value, whole_check,
+                **kwargs
+            )
+
+
+def _autofill_self_config(
+    config_path, config_key, config,
+    metadata,
+    **kwargs
+):
+    """Autofill config by metadata self section."""
+    if '_self' not in metadata:
+        if isinstance(config, dict):
+            _autofill_config(
+                config_path, config, metadata, **kwargs
+            )
+        return config
+    logging.debug(
+        'autofill %s by metadata %s', config_path, metadata['_self']
+    )
+    autofill_callback = metadata['_self'].get(
+        'autofill_callback', None
+    )
+    autofill_callback_params = metadata['_self'].get(
+        'autofill_callback_params', {}
+    )
+    callback_params = dict(kwargs)
+    if autofill_callback_params:
+        callback_params.update(autofill_callback_params)
+    default_value = metadata['_self'].get(
+        'default_value', None
+    )
+    if default_value is not None:
+        callback_params['default_value'] = default_value
+    options = metadata['_self'].get(
+        'options', None
+    )
+    if options is not None:
+        callback_params['options'] = options
+    if autofill_callback:
+        config = autofill_callback(
+            config_key, config, **callback_params
+        )
+    if config is None:
+        new_config = {}
+    else:
+        new_config = config
+    if isinstance(new_config, dict):
+        _autofill_config(
+            config_path, new_config, metadata, **kwargs
+        )
+        if new_config:
+            config = new_config
+    return config
+
+
+def _autofill_config(
+    config_path, config, metadata, **kwargs
+):
+    """autofill config by metadata."""
+    generals = {}
+    specified = {}
+    for key, value in metadata.items():
+        if key.startswith('$'):
+            generals[key] = value
+        elif key.startswith('_'):
+            pass
+        else:
+            specified[key] = value
+    config_keys = set(config.keys())
+    specified_keys = set(specified.keys())
+    intersect_keys = config_keys & specified_keys
+    not_found_keys = config_keys - specified_keys
+    redundant_keys = specified_keys - config_keys
+    for key in redundant_keys:
+        self_config = _autofill_self_config(
+            '%s/%s' % (config_path, key),
+            key, None, specified[key], **kwargs
+        )
+        if self_config is not None:
+            config[key] = self_config
+    for key in intersect_keys:
+        config[key] = _autofill_self_config(
+            '%s/%s' % (config_path, key),
+            key, config[key], specified[key],
+            **kwargs
+        )
+    for key in not_found_keys:
+        for general_key, general_value in generals.items():
+            config[key] = _autofill_self_config(
+                '%s/%s' % (config_path, key),
+                key, config[key], general_value,
+                **kwargs
+            )
+    return config
+
+
+def autofill_os_config(
+    config, os_id, **kwargs
+):
+    load_metadatas()
+    if os_id not in OS_METADATA_MAPPING:
+        raise exception.InvalidParameter(
+            'os %s is not found in os metadata mapping' % os_id
+        )
+
+    return _autofill_config(
+        '', config, OS_METADATA_MAPPING[os_id], **kwargs
+    )
+
+
+def autofill_package_config(
+    config, adapter_id, **kwargs
+):
+    load_metadatas()
+    if adapter_id not in PACKAGE_METADATA_MAPPING:
+        raise exception.InvalidParameter(
+            'adapter %s is not found in package metadata mapping' % adapter_id
+        )
+
+    return _autofill_config(
+        '', config, PACKAGE_METADATA_MAPPING[adapter_id], **kwargs
+    )
+
+
+def autofill_flavor_config(
+    config, flavor_id, **kwargs
+):
+    load_metadatas()
+    if not flavor_id:
+        logging.info('There is no flavor, skipping...')
+    elif flavor_id not in FLAVOR_METADATA_MAPPING:
+        raise exception.InvalidParameter(
+            'flavor %s is not found in flavor metadata mapping' % flavor_id
+        )
+    else:
+        return _autofill_config(
+            '', config, FLAVOR_METADATA_MAPPING[flavor_id], **kwargs
+        )
diff --git a/compass-tasks/db/api/network.py b/compass-tasks/db/api/network.py
new file mode 100644
index 0000000..e2bf7d3
--- /dev/null
+++ b/compass-tasks/db/api/network.py
@@ -0,0 +1,160 @@
+# Copyright 2014 Huawei Technologies Co. Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Network related database operations."""
+import logging
+import netaddr
+import re
+
+from compass.db.api import database
+from compass.db.api import permission
+from compass.db.api import user as user_api
+from compass.db.api import utils
+from compass.db import exception
+from compass.db import models
+
+
+SUPPORTED_FIELDS = ['subnet', 'name']
+RESP_FIELDS = [
+    'id', 'name', 'subnet', 'created_at', 'updated_at'
+]
+ADDED_FIELDS = ['subnet']
+OPTIONAL_ADDED_FIELDS = ['name']
+IGNORE_FIELDS = [
+    'id', 'created_at', 'updated_at'
+]
+UPDATED_FIELDS = ['subnet', 'name']
+
+
+def _check_subnet(subnet):
+    """Check subnet format is correct."""
+    try:
+        netaddr.IPNetwork(subnet)
+    except Exception as error:
+        logging.exception(error)
+        raise exception.InvalidParameter(
+            'subnet %s format unrecognized' % subnet)
+
+
+@utils.supported_filters(optional_support_keys=SUPPORTED_FIELDS)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_SUBNETS
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def list_subnets(user=None, session=None, **filters):
+    """List subnets."""
+    return utils.list_db_objects(
+        session, models.Subnet, **filters
+    )
+
+
+def _get_subnet(subnet_id, session=None, **kwargs):
+    """Get subnet by subnet id."""
+    if isinstance(subnet_id, (int, long)):
+        return utils.get_db_object(
+            session, models.Subnet,
+            id=subnet_id, **kwargs
+        )
+    raise exception.InvalidParameter(
+        'subnet id %s type is not int compatible' % subnet_id
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_SUBNETS
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def get_subnet(
+    subnet_id, exception_when_missing=True,
+    user=None, session=None, **kwargs
+):
+    """Get subnet info."""
+    return _get_subnet(
+        subnet_id, session=session,
+        exception_when_missing=exception_when_missing
+    )
+
+
+@utils.supported_filters(
+    ADDED_FIELDS, optional_support_keys=OPTIONAL_ADDED_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(subnet=_check_subnet)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_SUBNET
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def add_subnet(
+    exception_when_existing=True, subnet=None,
+    user=None, session=None, **kwargs
+):
+    """Create a subnet."""
+    return utils.add_db_object(
+        session, models.Subnet,
+        exception_when_existing, subnet, **kwargs
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(subnet=_check_subnet)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_SUBNET
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def update_subnet(subnet_id, user=None, session=None, **kwargs):
+    """Update a subnet."""
+    subnet = _get_subnet(
+        subnet_id, session=session
+    )
+    return utils.update_db_object(session, subnet, **kwargs)
+
+
+def _check_subnet_deletable(subnet):
+    """Check a subnet deletable."""
+    if subnet.host_networks:
+        host_networks = [
+            '%s:%s=%s' % (
+                host_network.host.name, host_network.interface,
+                host_network.ip
+            )
+            for host_network in subnet.host_networks
+        ]
+        raise exception.NotAcceptable(
+            'subnet %s contains host networks %s' % (
+                subnet.subnet, host_networks
+            )
+        )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEL_SUBNET
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def del_subnet(subnet_id, user=None, session=None, **kwargs):
+    """Delete a subnet."""
+    subnet = _get_subnet(
+        subnet_id, session=session
+    )
+    _check_subnet_deletable(subnet)
+    return utils.del_db_object(session, subnet)
diff --git a/compass-tasks/db/api/permission.py b/compass-tasks/db/api/permission.py
new file mode 100644
index 0000000..f4d777a
--- /dev/null
+++ b/compass-tasks/db/api/permission.py
@@ -0,0 +1,357 @@
+# Copyright 2014 Huawei Technologies Co. Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Permission database operations."""
+import re
+
+from compass.db.api import database
+from compass.db.api import user as user_api
+from compass.db.api import utils
+from compass.db import exception
+from compass.db import models
+from compass.utils import util
+
+
+SUPPORTED_FIELDS = ['id', 'name', 'alias', 'description']
+RESP_FIELDS = ['id', 'name', 'alias', 'description']
+
+
+class PermissionWrapper(object):
+    def __init__(self, name, alias, description):
+        self.name = name
+        self.alias = alias
+        self.description = description
+
+    def to_dict(self):
+        return {
+            'name': self.name,
+            'alias': self.alias,
+            'description': self.description
+        }
+
+
+PERMISSION_LIST_PERMISSIONS = PermissionWrapper(
+    'list_permissions', 'list permissions', 'list all permissions'
+)
+PERMISSION_LIST_SWITCHES = PermissionWrapper(
+    'list_switches', 'list switches', 'list all switches'
+)
+PERMISSION_LIST_SWITCH_FILTERS = PermissionWrapper(
+    'list_switch_filters',
+    'list switch filters',
+    'list switch filters'
+)
+PERMISSION_ADD_SWITCH = PermissionWrapper(
+    'add_switch', 'add switch', 'add switch'
+)
+PERMISSION_UPDATE_SWITCH_FILTERS = PermissionWrapper(
+    'update_switch_filters',
+    'update switch filters',
+    'update switch filters'
+)
+PERMISSION_DEL_SWITCH = PermissionWrapper(
+    'delete_switch', 'delete switch', 'delete switch'
+)
+PERMISSION_LIST_SWITCH_MACHINES = PermissionWrapper(
+    'list_switch_machines', 'list switch machines', 'list switch machines'
+)
+PERMISSION_ADD_SWITCH_MACHINE = PermissionWrapper(
+    'add_switch_machine', 'add switch machine', 'add switch machine'
+)
+PERMISSION_DEL_SWITCH_MACHINE = PermissionWrapper(
+    'del_switch_machine', 'delete switch machine', 'del switch machine'
+)
+PERMISSION_UPDATE_SWITCH_MACHINES = PermissionWrapper(
+    'update_switch_machines',
+    'update switch machines',
+    'update switch machines'
+)
+PERMISSION_LIST_MACHINES = PermissionWrapper(
+    'list_machines', 'list machines', 'list machines'
+)
+PERMISSION_ADD_MACHINE = PermissionWrapper(
+    'add_machine', 'add machine', 'add machine'
+)
+PERMISSION_DEL_MACHINE = PermissionWrapper(
+    'delete_machine', 'delete machine', 'delete machine'
+)
+PERMISSION_LIST_ADAPTERS = PermissionWrapper(
+    'list_adapters', 'list adapters', 'list adapters'
+)
+PERMISSION_LIST_METADATAS = PermissionWrapper(
+    'list_metadatas', 'list metadatas', 'list metadatas'
+)
+PERMISSION_LIST_SUBNETS = PermissionWrapper(
+    'list_subnets', 'list subnets', 'list subnets'
+)
+PERMISSION_ADD_SUBNET = PermissionWrapper(
+    'add_subnet', 'add subnet', 'add subnet'
+)
+PERMISSION_DEL_SUBNET = PermissionWrapper(
+    'del_subnet', 'del subnet', 'del subnet'
+)
+PERMISSION_LIST_CLUSTERS = PermissionWrapper(
+    'list_clusters', 'list clusters', 'list clusters'
+)
+PERMISSION_ADD_CLUSTER = PermissionWrapper(
+    'add_cluster', 'add cluster', 'add cluster'
+)
+PERMISSION_DEL_CLUSTER = PermissionWrapper(
+    'del_cluster', 'del cluster', 'del cluster'
+)
+PERMISSION_LIST_CLUSTER_CONFIG = PermissionWrapper(
+    'list_cluster_config', 'list cluster config', 'list cluster config'
+)
+PERMISSION_ADD_CLUSTER_CONFIG = PermissionWrapper(
+    'add_cluster_config', 'add cluster config', 'add cluster config'
+)
+PERMISSION_DEL_CLUSTER_CONFIG = PermissionWrapper(
+    'del_cluster_config', 'del cluster config', 'del cluster config'
+)
+PERMISSION_UPDATE_CLUSTER_HOSTS = PermissionWrapper(
+    'update_cluster_hosts',
+    'update cluster hosts',
+    'update cluster hosts'
+)
+PERMISSION_DEL_CLUSTER_HOST = PermissionWrapper(
+    'del_clusterhost', 'delete clusterhost', 'delete clusterhost'
+)
+PERMISSION_REVIEW_CLUSTER = PermissionWrapper(
+    'review_cluster', 'review cluster', 'review cluster'
+)
+PERMISSION_DEPLOY_CLUSTER = PermissionWrapper(
+    'deploy_cluster', 'deploy cluster', 'deploy cluster'
+)
+PERMISSION_DEPLOY_HOST = PermissionWrapper(
+    'deploy_host', 'deploy host', 'deploy host'
+)
+PERMISSION_GET_CLUSTER_STATE = PermissionWrapper(
+    'get_cluster_state', 'get cluster state', 'get cluster state'
+)
+PERMISSION_UPDATE_CLUSTER_STATE = PermissionWrapper(
+    'update_cluster_state', 'update cluster state',
+    'update cluster state'
+)
+PERMISSION_LIST_HOSTS = PermissionWrapper(
+    'list_hosts', 'list hosts', 'list hosts'
+)
+PERMISSION_LIST_HOST_CLUSTERS = PermissionWrapper(
+    'list_host_clusters',
+    'list host clusters',
+    'list host clusters'
+)
+PERMISSION_UPDATE_HOST = PermissionWrapper(
+    'update_host', 'update host', 'update host'
+)
+PERMISSION_DEL_HOST = PermissionWrapper(
+    'del_host', 'del host', 'del host'
+)
+PERMISSION_LIST_HOST_CONFIG = PermissionWrapper(
+    'list_host_config', 'list host config', 'list host config'
+)
+PERMISSION_ADD_HOST_CONFIG = PermissionWrapper(
+    'add_host_config', 'add host config', 'add host config'
+)
+PERMISSION_DEL_HOST_CONFIG = PermissionWrapper(
+    'del_host_config', 'del host config', 'del host config'
+)
+PERMISSION_LIST_HOST_NETWORKS = PermissionWrapper(
+    'list_host_networks',
+    'list host networks',
+    'list host networks'
+)
+PERMISSION_ADD_HOST_NETWORK = PermissionWrapper(
+    'add_host_network', 'add host network', 'add host network'
+)
+PERMISSION_DEL_HOST_NETWORK = PermissionWrapper(
+    'del_host_network', 'del host network', 'del host network'
+)
+PERMISSION_GET_HOST_STATE = PermissionWrapper(
+    'get_host_state', 'get host state', 'get host state'
+)
+PERMISSION_UPDATE_HOST_STATE = PermissionWrapper(
+    'update_host_state', 'update host sate', 'update host state'
+)
+PERMISSION_LIST_CLUSTERHOSTS = PermissionWrapper(
+    'list_clusterhosts', 'list cluster hosts', 'list cluster hosts'
+)
+PERMISSION_LIST_CLUSTERHOST_CONFIG = PermissionWrapper(
+    'list_clusterhost_config',
+    'list clusterhost config',
+    'list clusterhost config'
+)
+PERMISSION_ADD_CLUSTERHOST_CONFIG = PermissionWrapper(
+    'add_clusterhost_config',
+    'add clusterhost config',
+    'add clusterhost config'
+)
+PERMISSION_DEL_CLUSTERHOST_CONFIG = PermissionWrapper(
+    'del_clusterhost_config',
+    'del clusterhost config',
+    'del clusterhost config'
+)
+PERMISSION_GET_CLUSTERHOST_STATE = PermissionWrapper(
+    'get_clusterhost_state',
+    'get clusterhost state',
+    'get clusterhost state'
+)
+PERMISSION_UPDATE_CLUSTERHOST_STATE = PermissionWrapper(
+    'update_clusterhost_state',
+    'update clusterhost state',
+    'update clusterhost state'
+)
+PERMISSION_LIST_HEALTH_REPORT = PermissionWrapper(
+    'list_health_reports',
+    'list health check report',
+    'list health check report'
+)
+PERMISSION_GET_HEALTH_REPORT = PermissionWrapper(
+    'get_health_report',
+    'get health report',
+    'get health report'
+)
+PERMISSION_CHECK_CLUSTER_HEALTH = PermissionWrapper(
+    'start_check_cluster_health',
+    'start check cluster health',
+    'start check cluster health'
+)
+PERMISSION_SET_HEALTH_CHECK_ERROR = PermissionWrapper(
+    'set_error_state',
+    'set health check into error state',
+    'set health check into error state'
+)
+PERMISSION_DELETE_REPORT = PermissionWrapper(
+    'delete_reports',
+    'delete health reports',
+    'delete health reports'
+)
+PERMISSIONS = [
+    PERMISSION_LIST_PERMISSIONS,
+    PERMISSION_LIST_SWITCHES,
+    PERMISSION_ADD_SWITCH,
+    PERMISSION_DEL_SWITCH,
+    PERMISSION_LIST_SWITCH_FILTERS,
+    PERMISSION_UPDATE_SWITCH_FILTERS,
+    PERMISSION_LIST_SWITCH_MACHINES,
+    PERMISSION_ADD_SWITCH_MACHINE,
+    PERMISSION_DEL_SWITCH_MACHINE,
+    PERMISSION_UPDATE_SWITCH_MACHINES,
+    PERMISSION_LIST_MACHINES,
+    PERMISSION_ADD_MACHINE,
+    PERMISSION_DEL_MACHINE,
+    PERMISSION_LIST_ADAPTERS,
+    PERMISSION_LIST_METADATAS,
+    PERMISSION_LIST_SUBNETS,
+    PERMISSION_ADD_SUBNET,
+    PERMISSION_DEL_SUBNET,
+    PERMISSION_LIST_CLUSTERS,
+    PERMISSION_ADD_CLUSTER,
+    PERMISSION_DEL_CLUSTER,
+    PERMISSION_LIST_CLUSTER_CONFIG,
+    PERMISSION_ADD_CLUSTER_CONFIG,
+    PERMISSION_DEL_CLUSTER_CONFIG,
+    PERMISSION_UPDATE_CLUSTER_HOSTS,
+    PERMISSION_DEL_CLUSTER_HOST,
+    PERMISSION_REVIEW_CLUSTER,
+    PERMISSION_DEPLOY_CLUSTER,
+    PERMISSION_GET_CLUSTER_STATE,
+    PERMISSION_UPDATE_CLUSTER_STATE,
+    PERMISSION_LIST_HOSTS,
+    PERMISSION_LIST_HOST_CLUSTERS,
+    PERMISSION_UPDATE_HOST,
+    PERMISSION_DEL_HOST,
+    PERMISSION_LIST_HOST_CONFIG,
+    PERMISSION_ADD_HOST_CONFIG,
+    PERMISSION_DEL_HOST_CONFIG,
+    PERMISSION_LIST_HOST_NETWORKS,
+    PERMISSION_ADD_HOST_NETWORK,
+    PERMISSION_DEL_HOST_NETWORK,
+    PERMISSION_GET_HOST_STATE,
+    PERMISSION_UPDATE_HOST_STATE,
+    PERMISSION_DEPLOY_HOST,
+    PERMISSION_LIST_CLUSTERHOSTS,
+    PERMISSION_LIST_CLUSTERHOST_CONFIG,
+    PERMISSION_ADD_CLUSTERHOST_CONFIG,
+    PERMISSION_DEL_CLUSTERHOST_CONFIG,
+    PERMISSION_GET_CLUSTERHOST_STATE,
+    PERMISSION_UPDATE_CLUSTERHOST_STATE,
+    PERMISSION_LIST_HEALTH_REPORT,
+    PERMISSION_GET_HEALTH_REPORT,
+    PERMISSION_CHECK_CLUSTER_HEALTH,
+    PERMISSION_SET_HEALTH_CHECK_ERROR,
+    PERMISSION_DELETE_REPORT
+]
+
+
+@util.deprecated
+def list_permissions_internal(session, **filters):
+    """internal functions used only by other db.api modules."""
+    return utils.list_db_objects(session, models.Permission, **filters)
+
+
+@utils.supported_filters(optional_support_keys=SUPPORTED_FIELDS)
+@database.run_in_session()
+@user_api.check_user_permission(PERMISSION_LIST_PERMISSIONS)
+@utils.wrap_to_dict(RESP_FIELDS)
+def list_permissions(user=None, session=None, **filters):
+    """list permissions."""
+    return utils.list_db_objects(
+        session, models.Permission, **filters
+    )
+
+
+def _get_permission(permission_id, session=None, **kwargs):
+    """Get permission object by the unique key of Permission table."""
+    if isinstance(permission_id, (int, long)):
+        return utils.get_db_object(
+            session, models.Permission, id=permission_id, **kwargs)
+    raise exception.InvalidParameter(
+        'permission id %s type is not int compatible' % permission_id
+    )
+
+
+def get_permission_internal(permission_id, session=None, **kwargs):
+    return _get_permission(permission_id, session=session, **kwargs)
+
+
+@utils.supported_filters()
+@database.run_in_session()
+@user_api.check_user_permission(PERMISSION_LIST_PERMISSIONS)
+@utils.wrap_to_dict(RESP_FIELDS)
+def get_permission(
+    permission_id, exception_when_missing=True,
+    user=None, session=None, **kwargs
+):
+    """get permissions."""
+    return _get_permission(
+        permission_id, session=session,
+        exception_when_missing=exception_when_missing
+    )
+
+
+def add_permissions_internal(session=None):
+    """internal functions used by other db.api modules only."""
+    permissions = []
+    for permission in PERMISSIONS:
+        permissions.append(
+            utils.add_db_object(
+                session, models.Permission,
+                True,
+                permission.name,
+                alias=permission.alias,
+                description=permission.description
+            )
+        )
+
+    return permissions
diff --git a/compass-tasks/db/api/switch.py b/compass-tasks/db/api/switch.py
new file mode 100644
index 0000000..647eec0
--- /dev/null
+++ b/compass-tasks/db/api/switch.py
@@ -0,0 +1,1213 @@
+# Copyright 2014 Huawei Technologies Co. Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Switch database operations."""
+import logging
+import netaddr
+import re
+
+from compass.db.api import database
+from compass.db.api import permission
+from compass.db.api import user as user_api
+from compass.db.api import utils
+from compass.db import exception
+from compass.db import models
+from compass.utils import setting_wrapper as setting
+from compass.utils import util
+
+
+SUPPORTED_FIELDS = ['ip_int', 'vendor', 'state']
+SUPPORTED_FILTER_FIELDS = ['ip_int', 'vendor', 'state']
+SUPPORTED_SWITCH_MACHINES_FIELDS = [
+    'switch_ip_int', 'port', 'vlans', 'mac', 'tag', 'location',
+    'owner_id'
+]
+SUPPORTED_MACHINES_FIELDS = [
+    'port', 'vlans', 'mac', 'tag', 'location', 'owner_id'
+]
+SUPPORTED_SWITCH_MACHINES_HOSTS_FIELDS = [
+    'switch_ip_int', 'port', 'vlans', 'mac',
+    'tag', 'location', 'os_name'
+]
+SUPPORTED_MACHINES_HOSTS_FIELDS = [
+    'port', 'vlans', 'mac', 'tag', 'location',
+    'os_name'
+]
+IGNORE_FIELDS = ['id', 'created_at', 'updated_at']
+ADDED_FIELDS = ['ip']
+OPTIONAL_ADDED_FIELDS = [
+    'credentials', 'vendor', 'state', 'err_msg', 'machine_filters'
+]
+UPDATED_FIELDS = [
+    'ip', 'credentials', 'vendor', 'state',
+    'err_msg', 'put_machine_filters'
+]
+PATCHED_FIELDS = ['patched_credentials', 'patched_machine_filters']
+UPDATED_FILTERS_FIELDS = ['put_machine_filters']
+PATCHED_FILTERS_FIELDS = ['patched_machine_filters']
+ADDED_MACHINES_FIELDS = ['mac']
+OPTIONAL_ADDED_MACHINES_FIELDS = [
+    'ipmi_credentials', 'tag', 'location', 'owner_id'
+]
+ADDED_SWITCH_MACHINES_FIELDS = ['port']
+OPTIONAL_ADDED_SWITCH_MACHINES_FIELDS = ['vlans']
+UPDATED_MACHINES_FIELDS = [
+    'ipmi_credentials',
+    'tag', 'location'
+]
+UPDATED_SWITCH_MACHINES_FIELDS = ['port', 'vlans', 'owner_id']
+PATCHED_MACHINES_FIELDS = [
+    'patched_ipmi_credentials',
+    'patched_tag', 'patched_location'
+]
+PATCHED_SWITCH_MACHINES_FIELDS = ['patched_vlans']
+RESP_FIELDS = [
+    'id', 'ip', 'credentials', 'vendor', 'state', 'err_msg',
+    'filters', 'created_at', 'updated_at'
+]
+RESP_FILTERS_FIELDS = [
+    'id', 'ip', 'filters', 'created_at', 'updated_at'
+]
+RESP_ACTION_FIELDS = [
+    'status', 'details'
+]
+RESP_MACHINES_FIELDS = [
+    'id', 'switch_id', 'switch_ip', 'machine_id', 'switch_machine_id',
+    'port', 'vlans', 'mac', 'owner_id',
+    'ipmi_credentials', 'tag', 'location',
+    'created_at', 'updated_at'
+]
+RESP_MACHINES_HOSTS_FIELDS = [
+    'id', 'switch_id', 'switch_ip', 'machine_id', 'switch_machine_id',
+    'port', 'vlans', 'mac',
+    'ipmi_credentials', 'tag', 'location', 'ip',
+    'name', 'hostname', 'os_name', 'owner',
+    'os_installer', 'reinstall_os', 'os_installed',
+    'clusters', 'created_at', 'updated_at'
+]
+RESP_CLUSTER_FIELDS = [
+    'name', 'id'
+]
+
+
+def _check_machine_filters(machine_filters):
+    """Check if machine filters format is acceptable."""
+    logging.debug('check machine filters: %s', machine_filters)
+    models.Switch.parse_filters(machine_filters)
+
+
+def _check_vlans(vlans):
+    """Check vlans format is acceptable."""
+    for vlan in vlans:
+        if not isinstance(vlan, int):
+            raise exception.InvalidParameter(
+                'vlan %s is not int' % vlan
+            )
+
+
+@utils.supported_filters(
+    ADDED_FIELDS,
+    optional_support_keys=OPTIONAL_ADDED_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(
+    ip=utils.check_ip,
+    credentials=utils.check_switch_credentials,
+    machine_filters=_check_machine_filters
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def _add_switch(
+    ip, exception_when_existing=True,
+    machine_filters=setting.SWITCHES_DEFAULT_FILTERS,
+    session=None, **kwargs
+):
+    """Add switch by switch ip."""
+    ip_int = long(netaddr.IPAddress(ip))
+    return utils.add_db_object(
+        session, models.Switch, exception_when_existing, ip_int,
+        machine_filters=machine_filters, **kwargs
+    )
+
+
+def get_switch_internal(
+    switch_id, session=None, **kwargs
+):
+    """Get switch by switch id.
+
+    Should only be used by other files under db/api
+    """
+    return _get_switch(switch_id, session=session, **kwargs)
+
+
+def _get_switch(switch_id, session=None, **kwargs):
+    """Get Switch object switch id."""
+    if isinstance(switch_id, (int, long)):
+        return utils.get_db_object(
+            session, models.Switch,
+            id=switch_id, **kwargs
+        )
+    raise exception.InvalidParameter(
+        'switch id %s type is not int compatible' % switch_id)
+
+
+def _get_switch_by_ip(switch_ip, session=None, **kwargs):
+    """Get switch by switch ip."""
+    switch_ip_int = long(netaddr.IPAddress(switch_ip))
+    return utils.get_db_object(
+        session, models.Switch,
+        ip_int=switch_ip_int, **kwargs
+    )
+
+
+def _get_switch_machine(switch_id, machine_id, session=None, **kwargs):
+    """Get switch machine by switch id and machine id."""
+    switch = _get_switch(switch_id, session=session)
+    from compass.db.api import machine as machine_api
+    machine = machine_api.get_machine_internal(machine_id, session=session)
+    return utils.get_db_object(
+        session, models.SwitchMachine,
+        switch_id=switch.id, machine_id=machine.id, **kwargs
+    )
+
+
+def _get_switchmachine(switch_machine_id, session=None, **kwargs):
+    """Get switch machine by switch_machine_id."""
+    if not isinstance(switch_machine_id, (int, long)):
+        raise exception.InvalidParameter(
+            'switch machine id %s type is not int compatible' % (
+                switch_machine_id
+            )
+        )
+    return utils.get_db_object(
+        session, models.SwitchMachine,
+        switch_machine_id=switch_machine_id, **kwargs
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_SWITCHES
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def get_switch(
+    switch_id, exception_when_missing=True,
+    user=None, session=None, **kwargs
+):
+    """get a switch by switch id."""
+    return _get_switch(
+        switch_id, session=session,
+        exception_when_missing=exception_when_missing
+    )
+
+
+@utils.supported_filters(optional_support_keys=SUPPORTED_FIELDS)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_SWITCHES
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def list_switches(user=None, session=None, **filters):
+    """List switches."""
+    # TODO(xicheng): should discuss with weidong.
+    # If we can deprecate the use of DEFAULT_SWITCH_IP,
+    # The code will be simpler.
+    # The UI should use /machines-hosts instead of
+    # /switches-machines-hosts and can show multi switch ip/port
+    # under one row of machine info.
+    switches = utils.list_db_objects(
+        session, models.Switch, **filters
+    )
+    if 'ip_int' in filters:
+        return switches
+    else:
+        return [
+            switch for switch in switches
+            if switch.ip != setting.DEFAULT_SWITCH_IP
+        ]
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEL_SWITCH
+)
+@utils.wrap_to_dict(RESP_FIELDS)
+def del_switch(switch_id, user=None, session=None, **kwargs):
+    """Delete a switch.
+
+    If switch is not the default switch, and the machine under this switch
+    is only connected to this switch, the machine will be moved to connect
+    to default switch. Otherwise we can only simply delete the switch
+    machine. The purpose here to make sure there is no machine not
+    connecting to any switch.
+    """
+    # TODO(xicheng): Simplify the logic if the default switch feature
+    # can be deprecated.
+    switch = _get_switch(switch_id, session=session)
+    default_switch = _get_switch_by_ip(
+        setting.DEFAULT_SWITCH_IP, session=session
+    )
+    if switch.id != default_switch.id:
+        for switch_machine in switch.switch_machines:
+            machine = switch_machine.machine
+            if len(machine.switch_machines) <= 1:
+                utils.add_db_object(
+                    session, models.SwitchMachine,
+                    False,
+                    default_switch.id, machine.id,
+                    port=switch_machine.port
+                )
+    return utils.del_db_object(session, switch)
+
+
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_SWITCH
+)
+def add_switch(
+    exception_when_existing=True, ip=None,
+    user=None, session=None, **kwargs
+):
+    """Create a switch."""
+    return _add_switch(
+        ip,
+        exception_when_existing=exception_when_existing,
+        session=session, **kwargs
+    )
+
+
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_SWITCH
+)
+def add_switches(
+    exception_when_existing=False,
+    data=[], user=None, session=None
+):
+    """Create switches."""
+    # TODO(xicheng): simplify the batch api.
+    switches = []
+    fail_switches = []
+    for switch_data in data:
+        switch_object = _get_switch_by_ip(
+            switch_data['ip'], session=session,
+            exception_when_missing=False
+        )
+        if switch_object:
+            logging.error('ip %s exists in switch %s' % (
+                switch_data['ip'], switch_object.id
+            ))
+            fail_switches.append(switch_data)
+        else:
+            switches.append(
+                _add_switch(
+                    exception_when_existing=exception_when_existing,
+                    session=session,
+                    **switch_data
+                )
+            )
+    return {
+        'switches': switches,
+        'fail_switches': fail_switches
+    }
+
+
+@utils.wrap_to_dict(RESP_FIELDS)
+def _update_switch(switch_id, session=None, **kwargs):
+    """Update a switch."""
+    switch = _get_switch(switch_id, session=session)
+    return utils.update_db_object(session, switch, **kwargs)
+
+
+# replace machine_filters in kwargs to put_machine_filters,
+# which is used to tell db this is a put action for the field.
+@utils.replace_filters(
+    machine_filters='put_machine_filters'
+)
+@utils.supported_filters(
+    optional_support_keys=UPDATED_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(
+    credentials=utils.check_switch_credentials,
+    put_machine_filters=_check_machine_filters
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_SWITCH
+)
+def update_switch(switch_id, user=None, session=None, **kwargs):
+    """Update fields of a switch."""
+    return _update_switch(switch_id, session=session, **kwargs)
+
+
+# replace credentials to patched_credentials,
+# machine_filters to patched_machine_filters in kwargs.
+# This is to tell db they are patch action to the above fields.
+@utils.replace_filters(
+    credentials='patched_credentials',
+    machine_filters='patched_machine_filters'
+)
+@utils.supported_filters(
+    optional_support_keys=PATCHED_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(
+    patched_machine_filters=_check_machine_filters
+)
+@database.run_in_session()
+@utils.output_validates(
+    credentials=utils.check_switch_credentials
+)
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_SWITCH
+)
+def patch_switch(switch_id, user=None, session=None, **kwargs):
+    """Patch fields of a switch."""
+    return _update_switch(switch_id, session=session, **kwargs)
+
+
+@util.deprecated
+@utils.supported_filters(optional_support_keys=SUPPORTED_FILTER_FIELDS)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_SWITCH_FILTERS
+)
+@utils.wrap_to_dict(RESP_FILTERS_FIELDS)
+def list_switch_filters(user=None, session=None, **filters):
+    """List all switches' filters."""
+    return utils.list_db_objects(
+        session, models.Switch, **filters
+    )
+
+
+@util.deprecated
+@utils.supported_filters()
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_SWITCH_FILTERS
+)
+@utils.wrap_to_dict(RESP_FILTERS_FIELDS)
+def get_switch_filters(
+    switch_id, exception_when_missing=True,
+    user=None, session=None, **kwargs
+):
+    """get filters of a switch."""
+    return _get_switch(
+        switch_id, session=session,
+        exception_when_missing=exception_when_missing
+    )
+
+
+@util.deprecated
+@utils.replace_filters(
+    machine_filters='put_machine_filters'
+)
+@utils.supported_filters(
+    optional_support_keys=UPDATED_FILTERS_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(put_machine_filters=_check_machine_filters)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_SWITCH_FILTERS
+)
+@utils.wrap_to_dict(RESP_FILTERS_FIELDS)
+def update_switch_filters(switch_id, user=None, session=None, **kwargs):
+    """Update filters of a switch."""
+    switch = _get_switch(switch_id, session=session)
+    return utils.update_db_object(session, switch, **kwargs)
+
+
+@util.deprecated
+@utils.replace_filters(
+    machine_filters='patched_machine_filters'
+)
+@utils.supported_filters(
+    optional_support_keys=PATCHED_FILTERS_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(patched_machine_filters=_check_machine_filters)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_SWITCH_FILTERS
+)
+@utils.wrap_to_dict(RESP_FILTERS_FIELDS)
+def patch_switch_filter(switch_id, user=None, session=None, **kwargs):
+    """Patch filters to a switch."""
+    switch = _get_switch(switch_id, session=session)
+    return utils.update_db_object(session, switch, **kwargs)
+
+
+@util.deprecated
+def get_switch_machines_internal(session, **filters):
+    return utils.list_db_objects(
+        session, models.SwitchMachine, **filters
+    )
+
+
+def _filter_port(port_filter, obj):
+    """filter switch machines by port.
+
+    supported port_filter keys: [
+        'startswith', 'endswith', 'resp_lt',
+        'resp_le', 'resp_gt', 'resp_ge', 'resp_range'
+    ]
+
+    port_filter examples:
+        {
+            'startswitch': 'ae', 'endswith': '',
+            'resp_ge': 20, 'resp_le': 30,
+        }
+    """
+    port_prefix = port_filter.get('startswith', '')
+    port_suffix = port_filter.get('endswith', '')
+    pattern = re.compile(r'%s(\d+)%s' % (port_prefix, port_suffix))
+    match = pattern.match(obj)
+    if not match:
+        return False
+    port_number = int(match.group(1))
+    if (
+        'resp_lt' in port_filter and
+        port_number >= port_filter['resp_lt']
+    ):
+        return False
+    if (
+        'resp_le' in port_filter and
+        port_number > port_filter['resp_le']
+    ):
+        return False
+    if (
+        'resp_gt' in port_filter and
+        port_number <= port_filter['resp_gt']
+    ):
+        return False
+    if (
+        'resp_ge' in port_filter and
+        port_number < port_filter['resp_ge']
+    ):
+        return False
+    if 'resp_range' in port_filter:
+        resp_range = port_filter['resp_range']
+        if not isinstance(resp_range, list):
+            resp_range = [resp_range]
+        in_range = False
+        for port_start, port_end in resp_range:
+            if port_start <= port_number <= port_end:
+                in_range = True
+                break
+        if not in_range:
+            return False
+    return True
+
+
+def _filter_vlans(vlan_filter, obj):
+    """Filter switch machines by vlan.
+
+    supported keys in vlan_filter:
+        ['resp_in']
+    """
+    vlans = set(obj)
+    if 'resp_in' in vlan_filter:
+        resp_vlans = set(vlan_filter['resp_in'])
+        if not (vlans & resp_vlans):
+            return False
+    return True
+
+
+@utils.output_filters(
+    port=_filter_port, vlans=_filter_vlans,
+    tag=utils.general_filter_callback,
+    location=utils.general_filter_callback
+)
+@utils.wrap_to_dict(RESP_MACHINES_FIELDS)
+def _filter_switch_machines(switch_machines):
+    """Get filtered switch machines.
+
+    The filters are defined in each switch.
+    """
+    return [
+        switch_machine for switch_machine in switch_machines
+        if not switch_machine.filtered
+    ]
+
+
+@utils.output_filters(
+    missing_ok=True,
+    port=_filter_port, vlans=_filter_vlans,
+    tag=utils.general_filter_callback,
+    location=utils.general_filter_callback,
+    os_name=utils.general_filter_callback,
+)
+@utils.wrap_to_dict(
+    RESP_MACHINES_HOSTS_FIELDS,
+    clusters=RESP_CLUSTER_FIELDS
+)
+def _filter_switch_machines_hosts(switch_machines):
+    """Similar as _filter_switch_machines, but also return host info."""
+    filtered_switch_machines = [
+        switch_machine for switch_machine in switch_machines
+        if not switch_machine.filtered
+    ]
+    switch_machines_hosts = []
+    for switch_machine in filtered_switch_machines:
+        machine = switch_machine.machine
+        host = machine.host
+        if host:
+            switch_machine_host_dict = host.to_dict()
+        else:
+            switch_machine_host_dict = machine.to_dict()
+        switch_machine_host_dict.update(
+            switch_machine.to_dict()
+        )
+        switch_machines_hosts.append(switch_machine_host_dict)
+    return switch_machines_hosts
+
+
+@utils.supported_filters(
+    optional_support_keys=SUPPORTED_MACHINES_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_SWITCH_MACHINES
+)
+def list_switch_machines(
+    switch_id, user=None, session=None, **filters
+):
+    """Get switch machines of a switch."""
+    switch = _get_switch(switch_id, session=session)
+    switch_machines = utils.list_db_objects(
+        session, models.SwitchMachine, switch_id=switch.id, **filters
+    )
+    if not user.is_admin and len(switch_machines):
+        switch_machines = [m for m in switch_machines if m.machine.owner_id == user.id]
+    return _filter_switch_machines(switch_machines)
+
+
+# replace ip_int to switch_ip_int in kwargs
+@utils.replace_filters(
+    ip_int='switch_ip_int'
+)
+@utils.supported_filters(
+    optional_support_keys=SUPPORTED_SWITCH_MACHINES_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_SWITCH_MACHINES
+)
+def list_switchmachines(user=None, session=None, **filters):
+    """List switch machines."""
+    switch_machines = utils.list_db_objects(
+        session, models.SwitchMachine, **filters
+    )
+    return _filter_switch_machines(
+        switch_machines
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=SUPPORTED_MACHINES_HOSTS_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_SWITCH_MACHINES
+)
+def list_switch_machines_hosts(
+    switch_id, user=None, session=None, **filters
+):
+    """Get switch machines and possible hosts of a switch."""
+    switch = _get_switch(switch_id, session=session)
+    switch_machines = utils.list_db_objects(
+        session, models.SwitchMachine, switch_id=switch.id, **filters
+    )
+    return _filter_switch_machines_hosts(
+        switch_machines
+    )
+
+
+# replace ip_int to switch_ip_int in kwargs
+@utils.replace_filters(
+    ip_int='switch_ip_int'
+)
+@utils.supported_filters(
+    optional_support_keys=SUPPORTED_SWITCH_MACHINES_HOSTS_FIELDS
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_SWITCH_MACHINES
+)
+def list_switchmachines_hosts(user=None, session=None, **filters):
+    """List switch machines hnd possible hosts."""
+    switch_machines = utils.list_db_objects(
+        session, models.SwitchMachine, **filters
+    )
+    if not user.is_admin and len(switch_machines):
+        switch_machines = [m for m in switch_machines if m.machine.owner_id == user.id]
+    return _filter_switch_machines_hosts(
+        switch_machines
+    )
+
+
+@utils.supported_filters(
+    ADDED_MACHINES_FIELDS,
+    optional_support_keys=OPTIONAL_ADDED_MACHINES_FIELDS,
+    ignore_support_keys=OPTIONAL_ADDED_SWITCH_MACHINES_FIELDS
+)
+@utils.input_validates(mac=utils.check_mac)
+def _add_machine_if_not_exist(mac=None, session=None, **kwargs):
+    """Add machine if the mac does not exist in any machine."""
+    return utils.add_db_object(
+        session, models.Machine, False,
+        mac, **kwargs)
+
+
+@utils.supported_filters(
+    ADDED_SWITCH_MACHINES_FIELDS,
+    optional_support_keys=OPTIONAL_ADDED_SWITCH_MACHINES_FIELDS,
+    ignore_support_keys=OPTIONAL_ADDED_MACHINES_FIELDS
+)
+@utils.input_validates(vlans=_check_vlans)
+def _add_switch_machine_only(
+    switch, machine, exception_when_existing=True,
+    session=None, owner_id=None, port=None, **kwargs
+):
+    """add a switch machine."""
+    return utils.add_db_object(
+        session, models.SwitchMachine,
+        exception_when_existing,
+        switch.id, machine.id, port=port,
+        owner_id=owner_id,
+        **kwargs
+    )
+
+
+@utils.supported_filters(
+    ADDED_MACHINES_FIELDS + ADDED_SWITCH_MACHINES_FIELDS,
+    optional_support_keys=(
+        OPTIONAL_ADDED_MACHINES_FIELDS +
+        OPTIONAL_ADDED_SWITCH_MACHINES_FIELDS
+    ),
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.wrap_to_dict(RESP_MACHINES_FIELDS)
+def _add_switch_machine(
+    switch_id, exception_when_existing=True,
+    mac=None, port=None, session=None, owner_id=None, **kwargs
+):
+    """Add switch machine.
+
+    If underlying machine does not exist, also create the underlying
+    machine.
+    """
+    switch = _get_switch(switch_id, session=session)
+    machine = _add_machine_if_not_exist(
+        mac=mac, session=session, owner_id=owner_id, **kwargs
+    )
+    return _add_switch_machine_only(
+        switch, machine,
+        exception_when_existing,
+        port=port, session=session, **kwargs
+    )
+
+
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_SWITCH_MACHINE
+)
+def add_switch_machine(
+    switch_id, exception_when_existing=True,
+    mac=None, user=None, session=None,
+    owner_id=None, **kwargs
+):
+    """Add switch machine to a switch."""
+    return _add_switch_machine(
+        switch_id,
+        exception_when_existing=exception_when_existing,
+        mac=mac, session=session, owner_id=owner_id, **kwargs
+    )
+
+
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_SWITCH_MACHINE
+)
+@utils.wrap_to_dict(
+    [
+        'switches_machines',
+        'duplicate_switches_machines',
+        'fail_switches_machines'
+    ],
+    switches_machines=RESP_MACHINES_FIELDS,
+    duplicate_switches_machines=RESP_MACHINES_FIELDS
+)
+def add_switch_machines(
+    exception_when_existing=False,
+    data=[], user=None, session=None, owner_id=None
+):
+    """Add switch machines."""
+    switch_machines = []
+    duplicate_switch_machines = []
+    failed_switch_machines = []
+    switches_mapping = {}
+    switch_machines_mapping = {}
+    switch_ips = []
+    for item_data in data:
+        switch_ip = item_data['switch_ip']
+        if switch_ip not in switches_mapping:
+            switch_object = _get_switch_by_ip(
+                switch_ip, session=session,
+                exception_when_missing=False
+            )
+            if switch_object:
+                switch_ips.append(switch_ip)
+                switches_mapping[switch_ip] = switch_object
+            else:
+                logging.error(
+                    'switch %s does not exist' % switch_ip
+                )
+                item_data.pop('switch_ip')
+                failed_switch_machines.append(item_data)
+        else:
+            switch_object = switches_mapping[switch_ip]
+        if switch_object:
+            item_data.pop('switch_ip')
+            switch_machines_mapping.setdefault(
+                switch_object.id, []
+            ).append(item_data)
+
+    for switch_ip in switch_ips:
+        switch_object = switches_mapping[switch_ip]
+        switch_id = switch_object.id
+        machines = switch_machines_mapping[switch_id]
+        for machine in machines:
+            mac = machine['mac']
+            machine_object = _add_machine_if_not_exist(
+                mac=mac, session=session
+            )
+            switch_machine_object = _get_switch_machine(
+                switch_id, machine_object.id, session=session,
+                exception_when_missing=False
+            )
+            if switch_machine_object:
+                port = machine['port']
+                switch_machine_id = switch_machine_object.switch_machine_id
+                exist_port = switch_machine_object.port
+                if exist_port != port:
+                    logging.error(
+                        'switch machine %s exist port %s is '
+                        'different from added port %s' % (
+                            switch_machine_id,
+                            exist_port, port
+                        )
+                    )
+                    failed_switch_machines.append(machine)
+                else:
+                    logging.error(
+                        'iswitch machine %s is dulicate, '
+                        'will not be override' % switch_machine_id
+                    )
+                    duplicate_switch_machines.append(machine)
+            else:
+                del machine['mac']
+                switch_machines.append(_add_switch_machine_only(
+                    switch_object, machine_object,
+                    exception_when_existing,
+                    session=session, owner_id=owner_id, **machine
+                ))
+    return {
+        'switches_machines': switch_machines,
+        'duplicate_switches_machines': duplicate_switch_machines,
+        'fail_switches_machines': failed_switch_machines
+    }
+
+
+@utils.supported_filters(optional_support_keys=['find_machines'])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_SWITCH_MACHINES
+)
+@utils.wrap_to_dict(RESP_ACTION_FIELDS)
+def poll_switch(switch_id, user=None, session=None, **kwargs):
+    """poll switch to get machines."""
+    from compass.tasks import client as celery_client
+    switch = _get_switch(switch_id, session=session)
+    celery_client.celery.send_task(
+        'compass.tasks.pollswitch',
+        (user.email, switch.ip, switch.credentials),
+        queue=user.email,
+        exchange=user.email,
+        routing_key=user.email
+    )
+    return {
+        'status': 'action %s sent' % kwargs,
+        'details': {
+        }
+    }
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_SWITCH_MACHINES
+)
+@utils.wrap_to_dict(RESP_MACHINES_FIELDS)
+def get_switch_machine(
+    switch_id, machine_id, exception_when_missing=True,
+    user=None, session=None, **kwargs
+):
+    """get a switch machine by switch id and machine id."""
+    return _get_switch_machine(
+        switch_id, machine_id, session=session,
+        exception_when_missing=exception_when_missing
+    )
+
+
+@utils.supported_filters([])
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_LIST_SWITCH_MACHINES
+)
+@utils.wrap_to_dict(RESP_MACHINES_FIELDS)
+def get_switchmachine(
+    switch_machine_id, exception_when_missing=True,
+    user=None, session=None, **kwargs
+):
+    """get a switch machine by switch_machine_id."""
+    return _get_switchmachine(
+        switch_machine_id, session=session,
+        exception_when_missing=exception_when_missing
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=(
+        UPDATED_MACHINES_FIELDS + PATCHED_MACHINES_FIELDS
+    ),
+    ignore_support_keys=(
+        UPDATED_SWITCH_MACHINES_FIELDS + PATCHED_SWITCH_MACHINES_FIELDS
+    )
+)
+def _update_machine_if_necessary(
+    machine, session=None, **kwargs
+):
+    """Update machine is there is something to update."""
+    utils.update_db_object(
+        session, machine, **kwargs
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=(
+        UPDATED_SWITCH_MACHINES_FIELDS + PATCHED_SWITCH_MACHINES_FIELDS
+    ),
+    ignore_support_keys=(
+        UPDATED_MACHINES_FIELDS + PATCHED_MACHINES_FIELDS
+    )
+)
+def _update_switch_machine_only(switch_machine, session=None, **kwargs):
+    """Update switch machine."""
+    return utils.update_db_object(
+        session, switch_machine, **kwargs
+    )
+
+
+def _update_switch_machine(
+    switch_machine, session=None, **kwargs
+):
+    """Update switch machine.
+
+    If there are some attributes of underlying machine need to update,
+    also update them in underlying machine.
+    """
+    _update_machine_if_necessary(
+        switch_machine.machine, session=session, **kwargs
+    )
+    return _update_switch_machine_only(
+        switch_machine, session=session, **kwargs
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=(
+        UPDATED_MACHINES_FIELDS + UPDATED_SWITCH_MACHINES_FIELDS
+    ),
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(vlans=_check_vlans)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_SWITCH_MACHINE
+)
+@utils.wrap_to_dict(RESP_MACHINES_FIELDS)
+def update_switch_machine(
+    switch_id, machine_id, user=None,
+    session=None, **kwargs
+):
+    """Update switch machine by switch id and machine id."""
+    switch_machine = _get_switch_machine(
+        switch_id, machine_id, session=session
+    )
+    return _update_switch_machine(
+        switch_machine,
+        session=session, **kwargs
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=(
+        UPDATED_MACHINES_FIELDS + UPDATED_SWITCH_MACHINES_FIELDS
+    ),
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(vlans=_check_vlans)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_SWITCH_MACHINE
+)
+@utils.wrap_to_dict(RESP_MACHINES_FIELDS)
+def update_switchmachine(switch_machine_id, user=None, session=None, **kwargs):
+    """Update switch machine by switch_machine_id."""
+    switch_machine = _get_switchmachine(
+        switch_machine_id, session=session
+    )
+    return _update_switch_machine(
+        switch_machine,
+        session=session, **kwargs
+    )
+
+
+# replace [vlans, ipmi_credentials, tag, location] to
+# [patched_vlans, patched_ipmi_credentials, patched_tag,
+# patched_location] in kwargs. It tells db these fields will
+# be patched.
+@utils.replace_filters(
+    vlans='patched_vlans',
+    ipmi_credentials='patched_ipmi_credentials',
+    tag='patched_tag',
+    location='patched_location'
+)
+@utils.supported_filters(
+    optional_support_keys=(
+        PATCHED_MACHINES_FIELDS + PATCHED_SWITCH_MACHINES_FIELDS
+    ),
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(patched_vlans=_check_vlans)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_SWITCH_MACHINE
+)
+@utils.wrap_to_dict(RESP_MACHINES_FIELDS)
+def patch_switch_machine(
+    switch_id, machine_id, user=None,
+    session=None, **kwargs
+):
+    """Patch switch machine by switch_id and machine_id."""
+    switch_machine = _get_switch_machine(
+        switch_id, machine_id, session=session
+    )
+    return _update_switch_machine(
+        switch_machine,
+        session=session, **kwargs
+    )
+
+
+# replace [vlans, ipmi_credentials, tag, location] to
+# [patched_vlans, patched_ipmi_credentials, patched_tag,
+# patched_location] in kwargs. It tells db these fields will
+# be patched.
+@utils.replace_filters(
+    vlans='patched_vlans',
+    ipmi_credentials='patched_ipmi_credentials',
+    tag='patched_tag',
+    location='patched_location'
+)
+@utils.supported_filters(
+    optional_support_keys=(
+        PATCHED_MACHINES_FIELDS + PATCHED_SWITCH_MACHINES_FIELDS
+    ),
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(patched_vlans=_check_vlans)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_ADD_SWITCH_MACHINE
+)
+@utils.wrap_to_dict(RESP_MACHINES_FIELDS)
+def patch_switchmachine(switch_machine_id, user=None, session=None, **kwargs):
+    """Patch switch machine by switch_machine_id."""
+    switch_machine = _get_switchmachine(
+        switch_machine_id, session=session
+    )
+    return _update_switch_machine(
+        switch_machine,
+        session=session, **kwargs
+    )
+
+
+def _del_switch_machine(
+    switch_machine, session=None
+):
+    """Delete switch machine.
+
+    If this is the last switch machine associated to underlying machine,
+    add a switch machine record to default switch to make the machine
+    searchable.
+    """
+    default_switch = _get_switch_by_ip(
+        setting.DEFAULT_SWITCH_IP, session=session
+    )
+    machine = switch_machine.machine
+    if len(machine.switch_machines) <= 1:
+        utils.add_db_object(
+            session, models.SwitchMachine,
+            False,
+            default_switch.id, machine.id,
+            port=switch_machine.port
+        )
+    return utils.del_db_object(session, switch_machine)
+
+
+@utils.supported_filters()
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEL_SWITCH_MACHINE
+)
+@utils.wrap_to_dict(RESP_MACHINES_FIELDS)
+def del_switch_machine(
+    switch_id, machine_id, user=None,
+    session=None, **kwargs
+):
+    """Delete switch machine by switch id and machine id."""
+    switch_machine = _get_switch_machine(
+        switch_id, machine_id, session=session
+    )
+    return _del_switch_machine(switch_machine, session=session)
+
+
+@utils.supported_filters()
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_DEL_SWITCH_MACHINE
+)
+@utils.wrap_to_dict(RESP_MACHINES_FIELDS)
+def del_switchmachine(switch_machine_id, user=None, session=None, **kwargs):
+    """Delete switch machine by switch_machine_id."""
+    switch_machine = _get_switchmachine(
+        switch_machine_id, session=session
+    )
+    return _del_switch_machine(switch_machine, session=session)
+
+
+@utils.supported_filters(
+    ['machine_id'],
+    optional_support_keys=UPDATED_SWITCH_MACHINES_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+def _add_machine_to_switch(
+    switch_id, machine_id, session=None, **kwargs
+):
+    """Add machine to switch."""
+    switch = _get_switch(switch_id, session=session)
+    from compass.db.api import machine as machine_api
+    machine = machine_api.get_machine_internal(
+        machine_id, session=session
+    )
+    _add_switch_machine_only(
+        switch, machine, False,
+        owner_id=machine.owner_id, **kwargs
+    )
+
+
+def _add_machines(switch, machines, session=None):
+    """Add machines to switch.
+
+    Args:
+       machines: list of dict which contains attributes to
+                 add machine to switch.
+
+    machines example:
+       {{'machine_id': 1, 'port': 'ae20'}]
+    """
+    for machine in machines:
+        _add_machine_to_switch(
+            switch.id, session=session, **machine
+        )
+
+
+def _remove_machines(switch, machines, session=None):
+    """Remove machines from switch.
+
+    Args:
+        machines: list of machine id.
+
+    machines example:
+        [1,2]
+    """
+    utils.del_db_objects(
+        session, models.SwitchMachine,
+        switch_id=switch.id, machine_id=machines
+    )
+
+
+def _set_machines(switch, machines, session=None):
+    """Reset machines to a switch.
+
+    Args:
+       machines: list of dict which contains attributes to
+                 add machine to switch.
+
+    machines example:
+       {{'machine_id': 1, 'port': 'ae20'}]
+    """
+    utils.del_db_objects(
+        session, models.SwitchMachine,
+        switch_id=switch.id
+    )
+    for switch_machine in machines:
+        _add_machine_to_switch(
+            switch.id, session=session, **switch_machine
+        )
+
+
+@utils.supported_filters(
+    optional_support_keys=[
+        'add_machines', 'remove_machines', 'set_machines'
+    ]
+)
+@database.run_in_session()
+@user_api.check_user_permission(
+    permission.PERMISSION_UPDATE_SWITCH_MACHINES
+)
+@utils.wrap_to_dict(RESP_MACHINES_FIELDS)
+def update_switch_machines(
+    switch_id, add_machines=[], remove_machines=[],
+    set_machines=None, user=None, session=None, **kwargs
+):
+    """update switch's machines"""
+    switch = _get_switch(switch_id, session=session)
+    if remove_machines:
+        _remove_machines(
+            switch, remove_machines, session=session
+        )
+    if add_machines:
+        _add_machines(
+            switch, add_machines, session=session
+        )
+    if set_machines is not None:
+        _set_machines(
+            switch, set_machines, session=session
+        )
+    return switch.switch_machines
diff --git a/compass-tasks/db/api/user.py b/compass-tasks/db/api/user.py
new file mode 100644
index 0000000..db039eb
--- /dev/null
+++ b/compass-tasks/db/api/user.py
@@ -0,0 +1,553 @@
+# Copyright 2014 Huawei Technologies Co. Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""User database operations."""
+import datetime
+import functools
+import logging
+import re
+
+from flask.ext.login import UserMixin
+
+from compass.db.api import database
+from compass.db.api import utils
+from compass.db import exception
+from compass.db import models
+
+from compass.utils import setting_wrapper as setting
+from compass.utils import util
+
+
+SUPPORTED_FIELDS = ['email', 'is_admin', 'active']
+PERMISSION_SUPPORTED_FIELDS = ['name']
+SELF_UPDATED_FIELDS = ['email', 'firstname', 'lastname', 'password']
+ADMIN_UPDATED_FIELDS = ['is_admin', 'active']
+IGNORE_FIELDS = ['id', 'created_at', 'updated_at']
+UPDATED_FIELDS = [
+    'email', 'firstname', 'lastname', 'password', 'is_admin', 'active'
+]
+ADDED_FIELDS = ['email', 'password']
+OPTIONAL_ADDED_FIELDS = ['is_admin', 'active']
+PERMISSION_ADDED_FIELDS = ['permission_id']
+RESP_FIELDS = [
+    'id', 'email', 'is_admin', 'active', 'firstname',
+    'lastname', 'created_at', 'updated_at'
+]
+RESP_TOKEN_FIELDS = [
+    'id', 'user_id', 'token', 'expire_timestamp'
+]
+PERMISSION_RESP_FIELDS = [
+    'id', 'user_id', 'permission_id', 'name', 'alias', 'description',
+    'created_at', 'updated_at'
+]
+
+
+def _check_email(email):
+    """Check email is email format."""
+    if '@' not in email:
+        raise exception.InvalidParameter(
+            'there is no @ in email address %s.' % email
+        )
+
+
+def _check_user_permission(user, permission, session=None):
+    """Check user has permission."""
+    if not user:
+        logging.info('empty user means the call is from internal')
+        return
+    if user.is_admin:
+        return
+
+    user_permission = utils.get_db_object(
+        session, models.UserPermission,
+        False, user_id=user.id, name=permission.name
+    )
+    if not user_permission:
+        raise exception.Forbidden(
+            'user %s does not have permission %s' % (
+                user.email, permission.name
+            )
+        )
+
+
+def check_user_permission(permission):
+    """Decorator to check user having permission."""
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            user = kwargs.get('user')
+            if user is not None:
+                session = kwargs.get('session')
+                if session is None:
+                    raise exception.DatabaseException(
+                        'wrapper check_user_permission does not run in session'
+                    )
+                _check_user_permission(user, permission, session=session)
+                return func(*args, **kwargs)
+            else:
+                return func(*args, **kwargs)
+        return wrapper
+    return decorator
+
+
+def check_user_admin():
+    """Decorator to check user is admin."""
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            user = kwargs.get('user')
+            if user is not None:
+                if not user.is_admin:
+                    raise exception.Forbidden(
+                        'User %s is not admin.' % (
+                            user.email
+                        )
+                    )
+                return func(*args, **kwargs)
+            else:
+                return func(*args, **kwargs)
+        return wrapper
+    return decorator
+
+
+def check_user_admin_or_owner():
+    """Decorator to check user is admin or the owner of the resource."""
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(user_id, *args, **kwargs):
+            user = kwargs.get('user')
+            if user is not None:
+                session = kwargs.get('session')
+                if session is None:
+                    raise exception.DatabaseException(
+                        'wrapper check_user_admin_or_owner is '
+                        'not called in session'
+                    )
+                check_user = _get_user(user_id, session=session)
+                if not user.is_admin and user.id != check_user.id:
+                    raise exception.Forbidden(
+                        'User %s is not admin or the owner of user %s.' % (
+                            user.email, check_user.email
+                        )
+                    )
+
+                return func(
+                    user_id, *args, **kwargs
+                )
+            else:
+                return func(
+                    user_id, *args, **kwargs
+                )
+        return wrapper
+    return decorator
+
+
+def _add_user_permissions(user, session=None, **permission_filters):
+    """add permissions to a user."""
+    from compass.db.api import permission as permission_api
+    for api_permission in permission_api.list_permissions(
+        session=session, **permission_filters
+    ):
+        utils.add_db_object(
+            session, models.UserPermission, False,
+            user.id, api_permission['id']
+        )
+
+
+def _remove_user_permissions(user, session=None, **permission_filters):
+    """remove permissions from a user."""
+    from compass.db.api import permission as permission_api
+    permission_ids = [
+        api_permission['id']
+        for api_permission in permission_api.list_permissions(
+            session=session, **permission_filters
+        )
+    ]
+    utils.del_db_objects(
+        session, models.UserPermission,
+        user_id=user.id, permission_id=permission_ids
+    )
+
+
+def _set_user_permissions(user, session=None, **permission_filters):
+    """set permissions to a user."""
+    utils.del_db_objects(
+        session, models.UserPermission,
+        user_id=user.id
+    )
+    _add_user_permissions(session, user, **permission_filters)
+
+
+class UserWrapper(UserMixin):
+    """Wrapper class provided to flask."""
+
+    def __init__(
+        self, id, email, crypted_password,
+        active=True, is_admin=False,
+        expire_timestamp=None, token='', **kwargs
+    ):
+        self.id = id
+        self.email = email
+        self.password = crypted_password
+        self.active = active
+        self.is_admin = is_admin
+        self.expire_timestamp = expire_timestamp
+        if not token:
+            self.token = self.get_auth_token()
+        else:
+            self.token = token
+        super(UserWrapper, self).__init__()
+
+    def authenticate(self, password):
+        if not util.encrypt(password, self.password) == self.password:
+            raise exception.Unauthorized('%s password mismatch' % self.email)
+
+    def get_auth_token(self):
+        return util.encrypt(self.email)
+
+    def is_active(self):
+        return self.active
+
+    def get_id(self):
+        return self.token
+
+    def is_authenticated(self):
+        current_time = datetime.datetime.now()
+        return (
+            not self.expire_timestamp or
+            current_time < self.expire_timestamp
+        )
+
+    def __str__(self):
+        return '%s[email:%s,password:%s]' % (
+            self.__class__.__name__, self.email, self.password)
+
+
+@database.run_in_session()
+def get_user_object(email, session=None, **kwargs):
+    """get user and convert to UserWrapper object."""
+    user = utils.get_db_object(
+        session, models.User, False, email=email
+    )
+    if not user:
+        raise exception.Unauthorized(
+            '%s unauthorized' % email
+        )
+    user_dict = user.to_dict()
+    user_dict.update(kwargs)
+    return UserWrapper(**user_dict)
+
+
+@database.run_in_session(exception_when_in_session=False)
+def get_user_object_from_token(token, session=None):
+    """Get user from token and convert to UserWrapper object.
+
+    ::note:
+       get_user_object_from_token may be called in session.
+    """
+    expire_timestamp = {
+        'ge': datetime.datetime.now()
+    }
+    user_token = utils.get_db_object(
+        session, models.UserToken, False,
+        token=token, expire_timestamp=expire_timestamp
+    )
+    if not user_token:
+        raise exception.Unauthorized(
+            'invalid user token: %s' % token
+        )
+    user_dict = _get_user(
+        user_token.user_id, session=session
+    ).to_dict()
+    user_dict['token'] = token
+    expire_timestamp = user_token.expire_timestamp
+    user_dict['expire_timestamp'] = expire_timestamp
+    return UserWrapper(**user_dict)
+
+
+@utils.supported_filters()
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_TOKEN_FIELDS)
+def record_user_token(
+    token, expire_timestamp, user=None, session=None
+):
+    """record user token in database."""
+    user_token = utils.get_db_object(
+        session, models.UserToken, False,
+        user_id=user.id, token=token
+    )
+    if not user_token:
+        return utils.add_db_object(
+            session, models.UserToken, True,
+            token, user_id=user.id,
+            expire_timestamp=expire_timestamp
+        )
+    elif expire_timestamp > user_token.expire_timestamp:
+        return utils.update_db_object(
+            session, user_token, expire_timestamp=expire_timestamp
+        )
+    return user_token
+
+
+@utils.supported_filters()
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_TOKEN_FIELDS)
+def clean_user_token(token, user=None, session=None):
+    """clean user token in database."""
+    return utils.del_db_objects(
+        session, models.UserToken,
+        token=token, user_id=user.id
+    )
+
+
+def _get_user(user_id, session=None, **kwargs):
+    """Get user object by user id."""
+    if isinstance(user_id, (int, long)):
+        return utils.get_db_object(
+            session, models.User, id=user_id, **kwargs
+        )
+    raise exception.InvalidParameter(
+        'user id %s type is not int compatible' % user_id
+    )
+
+
+@utils.supported_filters()
+@database.run_in_session()
+@check_user_admin_or_owner()
+@utils.wrap_to_dict(RESP_FIELDS)
+def get_user(
+    user_id, exception_when_missing=True,
+    user=None, session=None, **kwargs
+):
+    """get a user."""
+    return _get_user(
+        user_id, session=session,
+        exception_when_missing=exception_when_missing
+    )
+
+
+@utils.supported_filters()
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_FIELDS)
+def get_current_user(
+    exception_when_missing=True, user=None,
+    session=None, **kwargs
+):
+    """get current user."""
+    return _get_user(
+        user.id, session=session,
+        exception_when_missing=exception_when_missing
+    )
+
+
+@utils.supported_filters(
+    optional_support_keys=SUPPORTED_FIELDS
+)
+@database.run_in_session()
+@check_user_admin()
+@utils.wrap_to_dict(RESP_FIELDS)
+def list_users(user=None, session=None, **filters):
+    """List all users."""
+    return utils.list_db_objects(
+        session, models.User, **filters
+    )
+
+
+@utils.input_validates(email=_check_email)
+@utils.supported_filters(
+    ADDED_FIELDS,
+    optional_support_keys=OPTIONAL_ADDED_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@check_user_admin()
+@utils.wrap_to_dict(RESP_FIELDS)
+def add_user(
+    exception_when_existing=True, user=None,
+    session=None, email=None, **kwargs
+):
+    """Create a user and return created user object."""
+    add_user = utils.add_db_object(
+        session, models.User,
+        exception_when_existing, email,
+        **kwargs)
+    _add_user_permissions(
+        add_user,
+        session=session,
+        name=setting.COMPASS_DEFAULT_PERMISSIONS
+    )
+    return add_user
+
+
+@utils.supported_filters()
+@database.run_in_session()
+@check_user_admin()
+@utils.wrap_to_dict(RESP_FIELDS)
+def del_user(user_id, user=None, session=None, **kwargs):
+    """delete a user and return the deleted user object."""
+    del_user = _get_user(user_id, session=session)
+    return utils.del_db_object(session, del_user)
+
+
+@utils.supported_filters(
+    optional_support_keys=UPDATED_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@utils.input_validates(email=_check_email)
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_FIELDS)
+def update_user(user_id, user=None, session=None, **kwargs):
+    """Update a user and return the updated user object."""
+    update_user = _get_user(
+        user_id, session=session,
+    )
+    allowed_fields = set()
+    if user.is_admin:
+        allowed_fields |= set(ADMIN_UPDATED_FIELDS)
+    if user.id == update_user.id:
+        allowed_fields |= set(SELF_UPDATED_FIELDS)
+    unsupported_fields = set(kwargs) - allowed_fields
+    if unsupported_fields:
+            # The user is not allowed to update a user.
+        raise exception.Forbidden(
+            'User %s has no permission to update user %s fields %s.' % (
+                user.email, user.email, unsupported_fields
+            )
+        )
+    return utils.update_db_object(session, update_user, **kwargs)
+
+
+@utils.supported_filters(optional_support_keys=PERMISSION_SUPPORTED_FIELDS)
+@database.run_in_session()
+@check_user_admin_or_owner()
+@utils.wrap_to_dict(PERMISSION_RESP_FIELDS)
+def get_permissions(
+    user_id, user=None, exception_when_missing=True,
+    session=None, **kwargs
+):
+    """List permissions of a user."""
+    get_user = _get_user(
+        user_id, session=session,
+        exception_when_missing=exception_when_missing
+    )
+    return utils.list_db_objects(
+        session, models.UserPermission, user_id=get_user.id, **kwargs
+    )
+
+
+def _get_permission(user_id, permission_id, session=None, **kwargs):
+    """Get user permission by user id and permission id."""
+    user = _get_user(user_id, session=session)
+    from compass.db.api import permission as permission_api
+    permission = permission_api.get_permission_internal(
+        permission_id, session=session
+    )
+    return utils.get_db_object(
+        session, models.UserPermission,
+        user_id=user.id, permission_id=permission.id,
+        **kwargs
+    )
+
+
+@utils.supported_filters()
+@database.run_in_session()
+@check_user_admin_or_owner()
+@utils.wrap_to_dict(PERMISSION_RESP_FIELDS)
+def get_permission(
+    user_id, permission_id, exception_when_missing=True,
+    user=None, session=None, **kwargs
+):
+    """Get a permission of a user."""
+    return _get_permission(
+        user_id, permission_id,
+        exception_when_missing=exception_when_missing,
+        session=session,
+        **kwargs
+    )
+
+
+@utils.supported_filters()
+@database.run_in_session()
+@check_user_admin_or_owner()
+@utils.wrap_to_dict(PERMISSION_RESP_FIELDS)
+def del_permission(user_id, permission_id, user=None, session=None, **kwargs):
+    """Delete a permission from a user."""
+    user_permission = _get_permission(
+        user_id, permission_id,
+        session=session, **kwargs
+    )
+    return utils.del_db_object(session, user_permission)
+
+
+@utils.supported_filters(
+    PERMISSION_ADDED_FIELDS,
+    ignore_support_keys=IGNORE_FIELDS
+)
+@database.run_in_session()
+@check_user_admin()
+@utils.wrap_to_dict(PERMISSION_RESP_FIELDS)
+def add_permission(
+    user_id, permission_id=None, exception_when_existing=True,
+    user=None, session=None
+):
+    """Add a permission to a user."""
+    get_user = _get_user(user_id, session=session)
+    from compass.db.api import permission as permission_api
+    get_permission = permission_api.get_permission_internal(
+        permission_id, session=session
+    )
+    return utils.add_db_object(
+        session, models.UserPermission, exception_when_existing,
+        get_user.id, get_permission.id
+    )
+
+
+def _get_permission_filters(permission_ids):
+    """Helper function to filter permissions."""
+    if permission_ids == 'all':
+        return {}
+    else:
+        return {'id': permission_ids}
+
+
+@utils.supported_filters(
+    optional_support_keys=[
+        'add_permissions', 'remove_permissions', 'set_permissions'
+    ]
+)
+@database.run_in_session()
+@check_user_admin()
+@utils.wrap_to_dict(PERMISSION_RESP_FIELDS)
+def update_permissions(
+    user_id, add_permissions=[], remove_permissions=[],
+    set_permissions=None, user=None, session=None, **kwargs
+):
+    """update user permissions."""
+    update_user = _get_user(user_id, session=session)
+    if remove_permissions:
+        _remove_user_permissions(
+            update_user, session=session,
+            **_get_permission_filters(remove_permissions)
+        )
+    if add_permissions:
+        _add_user_permissions(
+            update_user, session=session,
+            **_get_permission_filters(add_permissions)
+        )
+    if set_permissions is not None:
+        _set_user_permissions(
+            update_user, session=session,
+            **_get_permission_filters(set_permissions)
+        )
+    return update_user.user_permissions
diff --git a/compass-tasks/db/api/user_log.py b/compass-tasks/db/api/user_log.py
new file mode 100644
index 0000000..70de9db
--- /dev/null
+++ b/compass-tasks/db/api/user_log.py
@@ -0,0 +1,82 @@
+# Copyright 2014 Huawei Technologies Co. Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""UserLog database operations."""
+import logging
+
+from compass.db.api import database
+from compass.db.api import user as user_api
+from compass.db.api import utils
+from compass.db import exception
+from compass.db import models
+
+
+SUPPORTED_FIELDS = ['user_email', 'timestamp']
+USER_SUPPORTED_FIELDS = ['timestamp']
+RESP_FIELDS = ['user_id', 'action', 'timestamp']
+
+
+@database.run_in_session()
+def log_user_action(user_id, action, session=None):
+    """Log user action."""
+    utils.add_db_object(
+        session, models.UserLog, True, user_id=user_id, action=action
+    )
+
+
+@utils.supported_filters(optional_support_keys=USER_SUPPORTED_FIELDS)
+@database.run_in_session()
+@user_api.check_user_admin_or_owner()
+@utils.wrap_to_dict(RESP_FIELDS)
+def list_user_actions(user_id, user=None, session=None, **filters):
+    """list user actions of a user."""
+    list_user = user_api.get_user(user_id, user=user, session=session)
+    return utils.list_db_objects(
+        session, models.UserLog, order_by=['timestamp'],
+        user_id=list_user['id'], **filters
+    )
+
+
+@utils.supported_filters(optional_support_keys=SUPPORTED_FIELDS)
+@user_api.check_user_admin()
+@database.run_in_session()
+@utils.wrap_to_dict(RESP_FIELDS)
+def list_actions(user=None, session=None, **filters):
+    """list actions of all users."""
+    return utils.list_db_objects(
+        session, models.UserLog, order_by=['timestamp'], **filters
+    )
+
+
+@utils.supported_filters()
+@database.run_in_session()
+@user_api.check_user_admin_or_owner()
+@utils.wrap_to_dict(RESP_FIELDS)
+def del_user_actions(user_id, user=None, session=None, **filters):
+    """delete actions of a user."""
+    del_user = user_api.get_user(user_id, user=user, session=session)
+    return utils.del_db_objects(
+        session, models.UserLog, user_id=del_user['id'], **filters
+    )
+
+
+@utils.supported_filters()
+@database.run_in_session()
+@user_api.check_user_admin()
+@utils.wrap_to_dict(RESP_FIELDS)
+def del_actions(user=None, session=None, **filters):
+    """delete actions of all users."""
+    return utils.del_db_objects(
+        session, models.UserLog, **filters
+    )
diff --git a/compass-tasks/db/api/utils.py b/compass-tasks/db/api/utils.py
new file mode 100644
index 0000000..a44f26e
--- /dev/null
+++ b/compass-tasks/db/api/utils.py
@@ -0,0 +1,1286 @@
+# Copyright 2014 Huawei Technologies Co. Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Utils for database usage."""
+
+import functools
+import inspect
+import logging
+import netaddr
+import re
+
+from inspect import isfunction
+from sqlalchemy import and_
+from sqlalchemy import or_
+
+from compass.db import exception
+from compass.db import models
+from compass.utils import util
+
+
+def model_query(session, model):
+    """model query.
+
+    Return sqlalchemy query object.
+    """
+    if not issubclass(model, models.BASE):
+        raise exception.DatabaseException("model should be sublass of BASE!")
+
+    return session.query(model)
+
+
+def _default_list_condition_func(col_attr, value, condition_func):
+    """The default condition func for a list of data.
+
+    Given the condition func for single item of data, this function
+    wrap the condition_func and return another condition func using
+    or_ to merge the conditions of each single item to deal with a
+    list of data item.
+
+    Args:
+       col_attr: the colomn name
+       value: the column value need to be compared.
+       condition_func: the sqlalchemy condition object like ==
+
+    Examples:
+       col_attr is name, value is ['a', 'b', 'c'] and
+       condition_func is ==, the returned condition is
+       name == 'a' or name == 'b' or name == 'c'
+    """
+    conditions = []
+    for sub_value in value:
+        condition = condition_func(col_attr, sub_value)
+        if condition is not None:
+            conditions.append(condition)
+    if conditions:
+        return or_(*conditions)
+    else:
+        return None
+
+
+def _one_item_list_condition_func(col_attr, value, condition_func):
+    """The wrapper condition func to deal with one item data list.
+
+    For simplification, it is used to reduce generating too complex
+    sql conditions.
+    """
+    if value:
+        return condition_func(col_attr, value[0])
+    else:
+        return None
+
+
+def _model_condition_func(
+    col_attr, value,
+    item_condition_func,
+    list_condition_func=_default_list_condition_func
+):
+    """Return sql condition based on value type."""
+    if isinstance(value, list):
+        if not value:
+            return None
+        if len(value) == 1:
+            return item_condition_func(col_attr, value)
+        return list_condition_func(
+            col_attr, value, item_condition_func
+        )
+    else:
+        return item_condition_func(col_attr, value)
+
+
+def _between_condition(col_attr, value):
+    """Return sql range condition."""
+    if value[0] is not None and value[1] is not None:
+        return col_attr.between(value[0], value[1])
+    if value[0] is not None:
+        return col_attr >= value[0]
+    if value[1] is not None:
+        return col_attr <= value[1]
+    return None
+
+
+def model_order_by(query, model, order_by):
+    """append order by into sql query model."""
+    if not order_by:
+        return query
+    order_by_cols = []
+    for key in order_by:
+        if isinstance(key, tuple):
+            key, is_desc = key
+        else:
+            is_desc = False
+        if isinstance(key, basestring):
+            if hasattr(model, key):
+                col_attr = getattr(model, key)
+            else:
+                continue
+        else:
+            col_attr = key
+        if is_desc:
+            order_by_cols.append(col_attr.desc())
+        else:
+            order_by_cols.append(col_attr)
+    return query.order_by(*order_by_cols)
+
+
+def _model_condition(col_attr, value):
+    """Generate condition for one column.
+
+    Example for col_attr is name:
+        value is 'a': name == 'a'
+        value is ['a']: name == 'a'
+        value is ['a', 'b']: name == 'a' or name == 'b'
+        value is {'eq': 'a'}: name == 'a'
+        value is {'lt': 'a'}: name < 'a'
+        value is {'le': 'a'}: name <= 'a'
+        value is {'gt': 'a'}: name > 'a'
+        value is {'ge': 'a'}: name >= 'a'
+        value is {'ne': 'a'}: name != 'a'
+        value is {'in': ['a', 'b']}: name in ['a', 'b']
+        value is {'notin': ['a', 'b']}: name not in ['a', 'b']
+        value is {'startswith': 'abc'}: name like 'abc%'
+        value is {'endswith': 'abc'}: name like '%abc'
+        value is {'like': 'abc'}: name like '%abc%'
+        value is {'between': ('a', 'c')}: name >= 'a' and name <= 'c'
+        value is [{'lt': 'a'}]: name < 'a'
+        value is [{'lt': 'a'}, {'gt': c'}]: name < 'a' or name > 'c'
+        value is {'lt': 'c', 'gt': 'a'}: name > 'a' and name < 'c'
+
+    If value is a list, the condition is the or relationship among
+    conditions of each item.
+    If value is dict and there are multi keys in the dict, the relationship
+    is and conditions of each key.
+    Otherwise the condition is to compare the column with the value.
+    """
+    if isinstance(value, list):
+        basetype_values = []
+        composite_values = []
+        for item in value:
+            if isinstance(item, (list, dict)):
+                composite_values.append(item)
+            else:
+                basetype_values.append(item)
+        conditions = []
+        if basetype_values:
+            if len(basetype_values) == 1:
+                condition = (col_attr == basetype_values[0])
+            else:
+                condition = col_attr.in_(basetype_values)
+            conditions.append(condition)
+        for composite_value in composite_values:
+            condition = _model_condition(col_attr, composite_value)
+            if condition is not None:
+                conditions.append(condition)
+        if not conditions:
+            return None
+        if len(conditions) == 1:
+            return conditions[0]
+        return or_(*conditions)
+    elif isinstance(value, dict):
+        conditions = []
+        if 'eq' in value:
+            conditions.append(_model_condition_func(
+                col_attr, value['eq'],
+                lambda attr, data: attr == data,
+                lambda attr, data, item_condition_func: attr.in_(data)
+            ))
+        if 'lt' in value:
+            conditions.append(_model_condition_func(
+                col_attr, value['lt'],
+                lambda attr, data: attr < data,
+                _one_item_list_condition_func
+            ))
+        if 'gt' in value:
+            conditions.append(_model_condition_func(
+                col_attr, value['gt'],
+                lambda attr, data: attr > data,
+                _one_item_list_condition_func
+            ))
+        if 'le' in value:
+            conditions.append(_model_condition_func(
+                col_attr, value['le'],
+                lambda attr, data: attr <= data,
+                _one_item_list_condition_func
+            ))
+        if 'ge' in value:
+            conditions.append(_model_condition_func(
+                col_attr, value['ge'],
+                lambda attr, data: attr >= data,
+                _one_item_list_condition_func
+            ))
+        if 'ne' in value:
+            conditions.append(_model_condition_func(
+                col_attr, value['ne'],
+                lambda attr, data: attr != data,
+                lambda attr, data, item_condition_func: attr.notin_(data)
+            ))
+        if 'in' in value:
+            conditions.append(col_attr.in_(value['in']))
+        if 'notin' in value:
+            conditions.append(col_attr.notin_(value['notin']))
+        if 'startswith' in value:
+            conditions.append(_model_condition_func(
+                col_attr, value['startswith'],
+                lambda attr, data: attr.like('%s%%' % data)
+            ))
+        if 'endswith' in value:
+            conditions.append(_model_condition_func(
+                col_attr, value['endswith'],
+                lambda attr, data: attr.like('%%%s' % data)
+            ))
+        if 'like' in value:
+            conditions.append(_model_condition_func(
+                col_attr, value['like'],
+                lambda attr, data: attr.like('%%%s%%' % data)
+            ))
+        if 'between' in value:
+            conditions.append(_model_condition_func(
+                col_attr, value['between'],
+                _between_condition
+            ))
+        conditions = [
+            condition
+            for condition in conditions
+            if condition is not None
+        ]
+        if not conditions:
+            return None
+        if len(conditions) == 1:
+            return conditions[0]
+        return and_(conditions)
+    else:
+        condition = (col_attr == value)
+        return condition
+
+
+def model_filter(query, model, **filters):
+    """Append conditons to query for each possible column."""
+    for key, value in filters.items():
+        if isinstance(key, basestring):
+            if hasattr(model, key):
+                col_attr = getattr(model, key)
+            else:
+                continue
+        else:
+            col_attr = key
+        condition = _model_condition(col_attr, value)
+        if condition is not None:
+            query = query.filter(condition)
+    return query
+
+
+def replace_output(**output_mapping):
+    """Decorator to recursively relace output by output mapping.
+
+    The replacement detail is described in _replace_output.
+    """
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            return _replace_output(
+                func(*args, **kwargs), **output_mapping
+            )
+        return wrapper
+    return decorator
+
+
+def _replace_output(data, **output_mapping):
+    """Helper to replace output data.
+
+    Example:
+       data = {'a': 'hello'}
+       output_mapping = {'a': 'b'}
+       returns: {'b': 'hello'}
+
+       data = {'a': {'b': 'hello'}}
+       output_mapping =  {'a': 'b'}
+       returns: {'b': {'b': 'hello'}}
+
+       data = {'a': {'b': 'hello'}}
+       output_mapping =  {'a': {'b': 'c'}}
+       returns: {'a': {'c': 'hello'}}
+
+       data = [{'a': 'hello'}, {'a': 'hi'}]
+       output_mapping = {'a': 'b'}
+       returns: [{'b': 'hello'}, {'b': 'hi'}]
+    """
+    if isinstance(data, list):
+        return [
+            _replace_output(item, **output_mapping)
+            for item in data
+        ]
+    if not isinstance(data, dict):
+        raise exception.InvalidResponse(
+            '%s type is not dict' % data
+        )
+    info = {}
+    for key, value in data.items():
+        if key in output_mapping:
+            output_key = output_mapping[key]
+            if isinstance(output_key, basestring):
+                info[output_key] = value
+            else:
+                info[key] = (
+                    _replace_output(value, **output_key)
+                )
+        else:
+            info[key] = value
+    return info
+
+
+def get_wrapped_func(func):
+    """Get wrapped function instance.
+
+    Example:
+       @dec1
+       @dec2
+       myfunc(*args, **kwargs)
+
+       get_wrapped_func(myfunc) returns function object with
+       following attributes:
+          __name__: 'myfunc'
+          args: args
+          kwargs: kwargs
+       otherwise myfunc is function  object with following attributes:
+          __name__: partial object ...
+          args: ...
+          kwargs: ...
+    """
+    if func.func_closure:
+        for closure in func.func_closure:
+            if isfunction(closure.cell_contents):
+                return get_wrapped_func(closure.cell_contents)
+        return func
+    else:
+        return func
+
+
+def wrap_to_dict(support_keys=[], **filters):
+    """Decrator to convert returned object to dict.
+
+    The details is decribed in _wrapper_dict.
+    """
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            return _wrapper_dict(
+                func(*args, **kwargs), support_keys, **filters
+            )
+        return wrapper
+    return decorator
+
+
+def _wrapper_dict(data, support_keys, **filters):
+    """Helper for warpping db object into dictionary.
+
+    If data is list, convert it to a list of dict
+    If data is Base model, convert it to dict
+    for the data as a dict, filter it with the supported keys.
+    For each filter_key, filter_value  in filters, also filter
+    data[filter_key] by filter_value recursively if it exists.
+
+    Example:
+       data is models.Switch, it will be converted to
+       {
+           'id': 1, 'ip': '10.0.0.1', 'ip_int': 123456,
+           'credentials': {'version': 2, 'password': 'abc'}
+       }
+       Then if support_keys are ['id', 'ip', 'credentials'],
+       it will be filtered to {
+           'id': 1, 'ip': '10.0.0.1',
+           'credentials': {'version': 2, 'password': 'abc'}
+       }
+       Then if filters is {'credentials': ['version']},
+       it will be filtered to {
+           'id': 1, 'ip': '10.0.0.1',
+           'credentials': {'version': 2}
+       }
+    """
+    logging.debug(
+        'wrap dict %s by support_keys=%s filters=%s',
+        data, support_keys, filters
+    )
+    if isinstance(data, list):
+        return [
+            _wrapper_dict(item, support_keys, **filters)
+            for item in data
+        ]
+    if isinstance(data, models.HelperMixin):
+        data = data.to_dict()
+    if not isinstance(data, dict):
+        raise exception.InvalidResponse(
+            'response %s type is not dict' % data
+        )
+    info = {}
+    try:
+        for key in support_keys:
+            if key in data and data[key] is not None:
+                if key in filters:
+                    filter_keys = filters[key]
+                    if isinstance(filter_keys, dict):
+                        info[key] = _wrapper_dict(
+                            data[key], filter_keys.keys(),
+                            **filter_keys
+                        )
+                    else:
+                        info[key] = _wrapper_dict(
+                            data[key], filter_keys
+                        )
+                else:
+                    info[key] = data[key]
+        return info
+    except Exception as error:
+        logging.exception(error)
+        raise error
+
+
+def replace_filters(**kwarg_mapping):
+    """Decorator to replace kwargs.
+
+    Examples:
+       kwargs: {'a': 'b'}, kwarg_mapping: {'a': 'c'}
+       replaced kwargs to decorated func:
+          {'c': 'b'}
+
+    replace_filters is used to replace caller's input
+    to make it understandable by models.py.
+    """
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            replaced_kwargs = {}
+            for key, value in kwargs.items():
+                if key in kwarg_mapping:
+                    replaced_kwargs[kwarg_mapping[key]] = value
+                else:
+                    replaced_kwargs[key] = value
+            return func(*args, **replaced_kwargs)
+        return wrapper
+    return decorator
+
+
+def supported_filters(
+    support_keys=[],
+    optional_support_keys=[],
+    ignore_support_keys=[],
+):
+    """Decorator to check kwargs keys.
+
+    keys in kwargs and in ignore_support_keys will be removed.
+    If any unsupported keys found, a InvalidParameter
+    exception raises.
+
+    Args:
+       support_keys: keys that must exist.
+       optional_support_keys: keys that may exist.
+       ignore_support_keys: keys should be ignored.
+
+    Assumption: args without default value is supposed to exist.
+    You can add them in support_keys or not but we will make sure
+    it appears when we call the decorated function.
+    We do best match on both args and kwargs to make sure if the
+    key appears or not.
+
+    Examples:
+        decorated func: func(a, b, c=3, d=4, **kwargs)
+
+        support_keys=['e'] and call func(e=5):
+           raises: InvalidParameter: missing declared arg
+        support_keys=['e'] and call func(1,2,3,4,5,e=6):
+           raises: InvalidParameter: caller sending more args
+        support_keys=['e'] and call func(1,2):
+           raises: InvalidParameter: supported keys ['e'] missing
+        support_keys=['d', 'e'] and call func(1,2,e=3):
+           raises: InvalidParameter: supported keys ['d'] missing
+        support_keys=['d', 'e'] and call func(1,2,d=4, e=3):
+           passed
+        support_keys=['d'], optional_support_keys=['e']
+        and call func(1,2, d=3):
+           passed
+        support_keys=['d'], optional_support_keys=['e']
+        and call func(1,2, d=3, e=4, f=5):
+           raises: InvalidParameter: unsupported keys ['f']
+        support_keys=['d'], optional_support_keys=['e'],
+        ignore_support_keys=['f']
+        and call func(1,2, d=3, e=4, f=5):
+           passed to decorated keys: func(1,2, d=3, e=4)
+    """
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **filters):
+            wrapped_func = get_wrapped_func(func)
+            argspec = inspect.getargspec(wrapped_func)
+            wrapped_args = argspec.args
+            args_defaults = argspec.defaults
+            # wrapped_must_args are positional args caller must pass in.
+            if args_defaults:
+                wrapped_must_args = wrapped_args[:-len(args_defaults)]
+            else:
+                wrapped_must_args = wrapped_args[:]
+            # make sure any positional args without default value in
+            # decorated function should appear in args or filters.
+            if len(args) < len(wrapped_must_args):
+                remain_args = wrapped_must_args[len(args):]
+                for remain_arg in remain_args:
+                    if remain_arg not in filters:
+                        raise exception.InvalidParameter(
+                            'function missing declared arg %s '
+                            'while caller sends args %s' % (
+                                remain_arg, args
+                            )
+                        )
+            # make sure args should be no more than positional args
+            # declared in decorated function.
+            if len(args) > len(wrapped_args):
+                raise exception.InvalidParameter(
+                    'function definition args %s while the caller '
+                    'sends args %s' % (
+                        wrapped_args, args
+                    )
+                )
+            # exist_args are positional args caller has given.
+            exist_args = dict(zip(wrapped_args, args)).keys()
+            must_support_keys = set(support_keys)
+            all_support_keys = must_support_keys | set(optional_support_keys)
+            wrapped_supported_keys = set(filters) | set(exist_args)
+            unsupported_keys = (
+                set(filters) - set(wrapped_args) -
+                all_support_keys - set(ignore_support_keys)
+            )
+            # unsupported_keys are the keys that are not in support_keys,
+            # optional_support_keys, ignore_support_keys and are not passed in
+            # by positional args. It means the decorated function may
+            # not understand these parameters.
+            if unsupported_keys:
+                raise exception.InvalidParameter(
+                    'filter keys %s are not supported for %s' % (
+                        list(unsupported_keys), wrapped_func
+                    )
+                )
+            # missing_keys are the keys that must exist but missing in
+            # both positional args or kwargs.
+            missing_keys = must_support_keys - wrapped_supported_keys
+            if missing_keys:
+                raise exception.InvalidParameter(
+                    'filter keys %s not found for %s' % (
+                        list(missing_keys), wrapped_func
+                    )
+                )
+            # We filter kwargs to eliminate ignore_support_keys in kwargs
+            # passed to decorated function.
+            filtered_filters = dict([
+                (key, value)
+                for key, value in filters.items()
+                if key not in ignore_support_keys
+            ])
+            return func(*args, **filtered_filters)
+        return wrapper
+    return decorator
+
+
+def input_filters(
+    **filters
+):
+    """Decorator to filter kwargs.
+
+    For key in kwargs, if the key exists and filters
+    and the return of call filters[key] is False, the key
+    will be removed from kwargs.
+
+    The function definition of filters[key] is
+    func(value, *args, **kwargs) compared with decorated
+    function func(*args, **kwargs)
+
+    The function is used to filter kwargs in case some
+    kwargs should be removed conditionally depends on the
+    related filters.
+
+    Examples:
+       filters={'a': func(value, *args, **kwargs)}
+       @input_filters(**filters)
+       decorated_func(*args, **kwargs)
+       func returns False.
+       Then when call decorated_func(a=1, b=2)
+       it will be actually called the decorated func with
+       b=2. a=1 will be removed since it does not pass filtering.
+    """
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            filtered_kwargs = {}
+            for key, value in kwargs.items():
+                if key in filters:
+                    if filters[key](value, *args, **kwargs):
+                        filtered_kwargs[key] = value
+                    else:
+                        logging.debug(
+                            'ignore filtered input key %s' % key
+                        )
+                else:
+                    filtered_kwargs[key] = value
+            return func(*args, **filtered_kwargs)
+        return wrapper
+    return decorator
+
+
+def _obj_equal_or_subset(check, obj):
+    """Used by output filter to check if obj is in check."""
+    if check == obj:
+        return True
+    if not issubclass(obj.__class__, check.__class__):
+        return False
+    if isinstance(obj, dict):
+        return _dict_equal_or_subset(check, obj)
+    elif isinstance(obj, list):
+        return _list_equal_or_subset(check, obj)
+    else:
+        return False
+
+
+def _list_equal_or_subset(check_list, obj_list):
+    """Used by output filter to check if obj_list is in check_list"""
+    if not isinstance(check_list, list):
+        return False
+    return set(check_list).issubset(set(obj_list))
+
+
+def _dict_equal_or_subset(check_dict, obj_dict):
+    """Used by output filter to check if obj_dict in check_dict."""
+    if not isinstance(check_dict, dict):
+        return False
+    for key, value in check_dict.items():
+        if (
+            key not in obj_dict or
+            not _obj_equal_or_subset(check_dict[key], obj_dict[key])
+        ):
+            return False
+    return True
+
+
+def general_filter_callback(general_filter, obj):
+    """General filter function to filter output.
+
+    Since some fields stored in database is json encoded and
+    we want to do the deep match for the json encoded field to
+    do the filtering in some cases, we introduces the output_filters
+    and general_filter_callback to deal with this kind of cases.
+
+    We do special treatment for key 'resp_eq' to check if
+    obj is the recursively subset of general_filter['resp_eq']
+
+
+    Example:
+       obj: 'b'
+       general_filter: {}
+       returns: True
+
+       obj: 'b'
+       general_filter: {'resp_in': ['a', 'b']}
+       returns: True
+
+       obj: 'b'
+       general_filter: {'resp_in': ['a']}
+       returns: False
+
+       obj: 'b'
+       general_filter: {'resp_eq': 'b'}
+       returns: True
+
+       obj: 'b'
+       general_filter: {'resp_eq': 'a'}
+       returns: False
+
+       obj: 'b'
+       general_filter: {'resp_range': ('a', 'c')}
+       returns: True
+
+       obj: 'd'
+       general_filter: {'resp_range': ('a', 'c')}
+       returns: False
+
+    If there are multi keys in dict, the output is filtered
+    by and relationship.
+
+    If the general_filter is a list, the output is filtered
+    by or relationship.
+
+    Supported general filters: [
+        'resp_eq', 'resp_in', 'resp_lt',
+        'resp_le', 'resp_gt', 'resp_ge',
+        'resp_match', 'resp_range'
+    ]
+    """
+    if isinstance(general_filter, list):
+        if not general_filter:
+            return True
+        return any([
+            general_filter_callback(item, obj)
+            for item in general_filter
+        ])
+    elif isinstance(general_filter, dict):
+        if 'resp_eq' in general_filter:
+            if not _obj_equal_or_subset(
+                general_filter['resp_eq'], obj
+            ):
+                return False
+        if 'resp_in' in general_filter:
+            in_filters = general_filter['resp_in']
+            if not any([
+                _obj_equal_or_subset(in_filer, obj)
+                for in_filer in in_filters
+            ]):
+                return False
+        if 'resp_lt' in general_filter:
+            if obj >= general_filter['resp_lt']:
+                return False
+        if 'resp_le' in general_filter:
+            if obj > general_filter['resp_le']:
+                return False
+        if 'resp_gt' in general_filter:
+            if obj <= general_filter['resp_gt']:
+                return False
+        if 'resp_ge' in general_filter:
+            if obj < general_filter['resp_gt']:
+                return False
+        if 'resp_match' in general_filter:
+            if not re.match(general_filter['resp_match'], obj):
+                return False
+        if 'resp_range' in general_filter:
+            resp_range = general_filter['resp_range']
+            if not isinstance(resp_range, list):
+                resp_range = [resp_range]
+            in_range = False
+            for range_start, range_end in resp_range:
+                if range_start <= obj <= range_end:
+                    in_range = True
+            if not in_range:
+                return False
+        return True
+    else:
+        return True
+
+
+def filter_output(filter_callbacks, kwargs, obj, missing_ok=False):
+    """Filter ouput.
+
+    For each key in filter_callbacks, if it exists in kwargs,
+    kwargs[key] tells what we need to filter. If the call of
+    filter_callbacks[key] returns False, it tells the obj should be
+    filtered out of output.
+    """
+    for callback_key, callback_value in filter_callbacks.items():
+        if callback_key not in kwargs:
+            continue
+        if callback_key not in obj:
+            if missing_ok:
+                continue
+            else:
+                raise exception.InvalidResponse(
+                    '%s is not in %s' % (callback_key, obj)
+                )
+        if not callback_value(
+            kwargs[callback_key], obj[callback_key]
+        ):
+            return False
+    return True
+
+
+def output_filters(missing_ok=False, **filter_callbacks):
+    """Decorator to filter output list.
+
+    Each filter_callback should have the definition like:
+       func({'resp_eq': 'a'}, 'a')
+    """
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            filtered_obj_list = []
+            obj_list = func(*args, **kwargs)
+            for obj in obj_list:
+                if filter_output(
+                    filter_callbacks, kwargs, obj, missing_ok
+                ):
+                    filtered_obj_list.append(obj)
+            return filtered_obj_list
+        return wrapper
+    return decorator
+
+
+def _input_validates(args_validators, kwargs_validators, *args, **kwargs):
+    """Used by input_validators to validate inputs."""
+    for i, value in enumerate(args):
+        if i < len(args_validators) and args_validators[i]:
+            args_validators[i](value)
+    for key, value in kwargs.items():
+        if kwargs_validators.get(key):
+            kwargs_validators[key](value)
+
+
+def input_validates(*args_validators, **kwargs_validators):
+    """Decorator to validate input.
+
+    Each validator should have definition like:
+       func('00:01:02:03:04:05')
+    """
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            _input_validates(
+                args_validators, kwargs_validators,
+                *args, **kwargs
+            )
+            return func(*args, **kwargs)
+        return wrapper
+    return decorator
+
+
+def _input_validates_with_args(
+    args_validators, kwargs_validators, *args, **kwargs
+):
+    """Validate input with validators.
+
+    Each validator takes the arguments of the decorated function
+    as its arguments. The function definition is like:
+       func(value, *args, **kwargs) compared with the decorated
+       function func(*args, **kwargs).
+    """
+    for i, value in enumerate(args):
+        if i < len(args_validators) and args_validators[i]:
+            args_validators[i](value, *args, **kwargs)
+    for key, value in kwargs.items():
+        if kwargs_validators.get(key):
+            kwargs_validators[key](value, *args, **kwargs)
+
+
+def input_validates_with_args(
+    *args_validators, **kwargs_validators
+):
+    """Decorator to validate input."""
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            _input_validates_with_args(
+                args_validators, kwargs_validators,
+                *args, **kwargs
+            )
+            return func(*args, **kwargs)
+        return wrapper
+    return decorator
+
+
+def _output_validates_with_args(
+    kwargs_validators, obj, *args, **kwargs
+):
+    """Validate output with validators.
+
+    Each validator takes the arguments of the decorated function
+    as its arguments. The function definition is like:
+       func(value, *args, **kwargs) compared with the decorated
+       function func(*args, **kwargs).
+    """
+    if isinstance(obj, list):
+        for item in obj:
+            _output_validates_with_args(
+                kwargs_validators, item, *args, **kwargs
+            )
+        return
+    if isinstance(obj, models.HelperMixin):
+        obj = obj.to_dict()
+    if not isinstance(obj, dict):
+        raise exception.InvalidResponse(
+            'response %s type is not dict' % str(obj)
+        )
+    try:
+        for key, value in obj.items():
+            if key in kwargs_validators:
+                kwargs_validators[key](value, *args, **kwargs)
+    except Exception as error:
+        logging.exception(error)
+        raise error
+
+
+def output_validates_with_args(**kwargs_validators):
+    """Decorator to validate output.
+
+    The validator can take the arguments of the decorated
+    function as its arguments.
+    """
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            obj = func(*args, **kwargs)
+            if isinstance(obj, list):
+                for obj_item in obj:
+                    _output_validates_with_args(
+                        kwargs_validators, obj_item,
+                        *args, **kwargs
+                    )
+            else:
+                _output_validates_with_args(
+                    kwargs_validators, obj,
+                    *args, **kwargs
+                )
+            return obj
+        return wrapper
+    return decorator
+
+
+def _output_validates(kwargs_validators, obj):
+    """Validate output.
+
+    Each validator has following signature:
+       func(value)
+    """
+    if isinstance(obj, list):
+        for item in obj:
+            _output_validates(kwargs_validators, item)
+        return
+    if isinstance(obj, models.HelperMixin):
+        obj = obj.to_dict()
+    if not isinstance(obj, dict):
+        raise exception.InvalidResponse(
+            'response %s type is not dict' % str(obj)
+        )
+    try:
+        for key, value in obj.items():
+            if key in kwargs_validators:
+                kwargs_validators[key](value)
+    except Exception as error:
+        logging.exception(error)
+        raise error
+
+
+def output_validates(**kwargs_validators):
+    """Decorator to validate output."""
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            obj = func(*args, **kwargs)
+            if isinstance(obj, list):
+                for obj_item in obj:
+                    _output_validates(kwargs_validators, obj_item)
+            else:
+                _output_validates(kwargs_validators, obj)
+            return obj
+        return wrapper
+    return decorator
+
+
+def get_db_object(session, table, exception_when_missing=True, **kwargs):
+    """Get db object.
+
+    If not exception_when_missing and the db object can not be found,
+    return None instead of raising exception.
+    """
+    if not session:
+        raise exception.DatabaseException('session param is None')
+    with session.begin(subtransactions=True):
+        logging.debug(
+            'session %s get db object %s from table %s',
+            id(session), kwargs, table.__name__)
+        db_object = model_filter(
+            model_query(session, table), table, **kwargs
+        ).first()
+        logging.debug(
+            'session %s got db object %s', id(session), db_object
+        )
+        if db_object:
+            return db_object
+
+        if not exception_when_missing:
+            return None
+
+        raise exception.RecordNotExists(
+            'Cannot find the record in table %s: %s' % (
+                table.__name__, kwargs
+            )
+        )
+
+
+def add_db_object(session, table, exception_when_existing=True,
+                  *args, **kwargs):
+    """Create db object.
+
+    If not exception_when_existing and the db object exists,
+    Instead of raising exception, updating the existing db object.
+    """
+    if not session:
+        raise exception.DatabaseException('session param is None')
+    with session.begin(subtransactions=True):
+        logging.debug(
+            'session %s add object %s atributes %s to table %s',
+            id(session), args, kwargs, table.__name__)
+        argspec = inspect.getargspec(table.__init__)
+        arg_names = argspec.args[1:]
+        arg_defaults = argspec.defaults
+        if not arg_defaults:
+            arg_defaults = []
+        if not (
+            len(arg_names) - len(arg_defaults) <= len(args) <= len(arg_names)
+        ):
+            raise exception.InvalidParameter(
+                'arg names %s does not match arg values %s' % (
+                    arg_names, args)
+            )
+        db_keys = dict(zip(arg_names, args))
+        if db_keys:
+            db_object = session.query(table).filter_by(**db_keys).first()
+        else:
+            db_object = None
+
+        new_object = False
+        if db_object:
+            logging.debug(
+                'got db object %s: %s', db_keys, db_object
+            )
+            if exception_when_existing:
+                raise exception.DuplicatedRecord(
+                    '%s exists in table %s' % (db_keys, table.__name__)
+                )
+        else:
+            db_object = table(**db_keys)
+            new_object = True
+
+        for key, value in kwargs.items():
+            setattr(db_object, key, value)
+
+        if new_object:
+            session.add(db_object)
+        session.flush()
+        db_object.initialize()
+        db_object.validate()
+        logging.debug(
+            'session %s db object %s added', id(session), db_object
+        )
+        return db_object
+
+
+def list_db_objects(session, table, order_by=[], **filters):
+    """List db objects.
+
+    If order by given, the db objects should be sorted by the ordered keys.
+    """
+    if not session:
+        raise exception.DatabaseException('session param is None')
+    with session.begin(subtransactions=True):
+        logging.debug(
+            'session %s list db objects by filters %s in table %s',
+            id(session), filters, table.__name__
+        )
+        db_objects = model_order_by(
+            model_filter(
+                model_query(session, table),
+                table,
+                **filters
+            ),
+            table,
+            order_by
+        ).all()
+        logging.debug(
+            'session %s got listed db objects: %s',
+            id(session), db_objects
+        )
+        return db_objects
+
+
+def del_db_objects(session, table, **filters):
+    """delete db objects."""
+    if not session:
+        raise exception.DatabaseException('session param is None')
+    with session.begin(subtransactions=True):
+        logging.debug(
+            'session %s delete db objects by filters %s in table %s',
+            id(session), filters, table.__name__
+        )
+        query = model_filter(
+            model_query(session, table), table, **filters
+        )
+        db_objects = query.all()
+        query.delete(synchronize_session=False)
+        logging.debug(
+            'session %s db objects %s deleted', id(session), db_objects
+        )
+        return db_objects
+
+
+def update_db_objects(session, table, updates={}, **filters):
+    """Update db objects."""
+    if not session:
+        raise exception.DatabaseException('session param is None')
+    with session.begin(subtransactions=True):
+        logging.debug(
+            'session %s update db objects by filters %s in table %s',
+            id(session), filters, table.__name__)
+        db_objects = model_filter(
+            model_query(session, table), table, **filters
+        ).all()
+        for db_object in db_objects:
+            logging.debug('update db object %s: %s', db_object, updates)
+            update_db_object(session, db_object, **updates)
+        logging.debug(
+            'session %s db objects %s updated',
+            id(session), db_objects
+        )
+        return db_objects
+
+
+def update_db_object(session, db_object, **kwargs):
+    """Update db object."""
+    if not session:
+        raise exception.DatabaseException('session param is None')
+    with session.begin(subtransactions=True):
+        logging.debug(
+            'session %s update db object %s by value %s',
+            id(session), db_object, kwargs
+        )
+        for key, value in kwargs.items():
+            setattr(db_object, key, value)
+        session.flush()
+        db_object.update()
+        db_object.validate()
+        logging.debug(
+            'session %s db object %s updated',
+            id(session), db_object
+        )
+        return db_object
+
+
+def del_db_object(session, db_object):
+    """Delete db object."""
+    if not session:
+        raise exception.DatabaseException('session param is None')
+    with session.begin(subtransactions=True):
+        logging.debug(
+            'session %s delete db object %s',
+            id(session), db_object
+        )
+        session.delete(db_object)
+        logging.debug(
+            'session %s db object %s deleted',
+            id(session), db_object
+        )
+        return db_object
+
+
+def check_ip(ip):
+    """Check ip is ip address formatted."""
+    try:
+        netaddr.IPAddress(ip)
+    except Exception as error:
+        logging.exception(error)
+        raise exception.InvalidParameter(
+            'ip address %s format uncorrect' % ip
+        )
+
+
+def check_mac(mac):
+    """Check mac is mac address formatted."""
+    try:
+        netaddr.EUI(mac)
+    except Exception as error:
+        logging.exception(error)
+        raise exception.InvalidParameter(
+            'invalid mac address %s' % mac
+        )
+
+
+NAME_PATTERN = re.compile(r'[a-zA-Z0-9][a-zA-Z0-9_-]*')
+
+
+def check_name(name):
+    """Check name meeting name format requirement."""
+    if not NAME_PATTERN.match(name):
+        raise exception.InvalidParameter(
+            'name %s does not match the pattern %s' % (
+                name, NAME_PATTERN.pattern
+            )
+        )
+
+
+def _check_ipmi_credentials_ip(ip):
+    check_ip(ip)
+
+
+def check_ipmi_credentials(ipmi_credentials):
+    """Check ipmi credentials format is correct."""
+    if not ipmi_credentials:
+        return
+    if not isinstance(ipmi_credentials, dict):
+        raise exception.InvalidParameter(
+            'invalid ipmi credentials %s' % ipmi_credentials
+
+        )
+    for key in ipmi_credentials:
+        if key not in ['ip', 'username', 'password']:
+            raise exception.InvalidParameter(
+                'unrecognized field %s in ipmi credentials %s' % (
+                    key, ipmi_credentials
+                )
+            )
+    for key in ['ip', 'username', 'password']:
+        if key not in ipmi_credentials:
+            raise exception.InvalidParameter(
+                'no field %s in ipmi credentials %s' % (
+                    key, ipmi_credentials
+                )
+            )
+        check_ipmi_credential_field = '_check_ipmi_credentials_%s' % key
+        this_module = globals()
+        if check_ipmi_credential_field in this_module:
+            this_module[check_ipmi_credential_field](
+                ipmi_credentials[key]
+            )
+        else:
+            logging.debug(
+                'function %s is not defined', check_ipmi_credential_field
+            )
+
+
+def _check_switch_credentials_version(version):
+    if version not in ['1', '2c', '3']:
+        raise exception.InvalidParameter(
+            'unknown snmp version %s' % version
+        )
+
+
+def check_switch_credentials(credentials):
+    """Check switch credentials format is correct."""
+    if not credentials:
+        return
+    if not isinstance(credentials, dict):
+        raise exception.InvalidParameter(
+            'credentials %s is not dict' % credentials
+        )
+    for key in credentials:
+        if key not in ['version', 'community']:
+            raise exception.InvalidParameter(
+                'unrecognized key %s in credentials %s' % (key, credentials)
+            )
+    for key in ['version', 'community']:
+        if key not in credentials:
+            raise exception.InvalidParameter(
+                'there is no %s field in credentials %s' % (key, credentials)
+            )
+
+        key_check_func_name = '_check_switch_credentials_%s' % key
+        this_module = globals()
+        if key_check_func_name in this_module:
+            this_module[key_check_func_name](
+                credentials[key]
+            )
+        else:
+            logging.debug(
+                'function %s is not defined',
+                key_check_func_name
+            )