1 files changed, 128 insertions, 0 deletions
diff --git a/charms/trusty/ceilometer-agent/hooks/charmhelpers/contrib/openstack/ha/utils.py b/charms/trusty/ceilometer-agent/hooks/charmhelpers/contrib/openstack/ha/utils.py
new file mode 100644
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+++ b/charms/trusty/ceilometer-agent/hooks/charmhelpers/contrib/openstack/ha/utils.py
@@ -0,0 +1,128 @@
+# Copyright 2014-2016 Canonical Limited.
+#
+# 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.
+
+#
+# Copyright 2016 Canonical Ltd.
+#
+# Authors:
+#  Openstack Charmers <
+#
+
+"""
+Helpers for high availability.
+"""
+
+import re
+
+from charmhelpers.core.hookenv import (
+    log,
+    relation_set,
+    charm_name,
+    config,
+    status_set,
+    DEBUG,
+)
+
+from charmhelpers.core.host import (
+    lsb_release
+)
+
+from charmhelpers.contrib.openstack.ip import (
+    resolve_address,
+)
+
+
+class DNSHAException(Exception):
+    """Raised when an error occurs setting up DNS HA
+    """
+
+    pass
+
+
+def update_dns_ha_resource_params(resources, resource_params,
+                                  relation_id=None,
+                                  crm_ocf='ocf:maas:dns'):
+    """ Check for os-*-hostname settings and update resource dictionaries for
+    the HA relation.
+
+    @param resources: Pointer to dictionary of resources.
+                      Usually instantiated in ha_joined().
+    @param resource_params: Pointer to dictionary of resource parameters.
+                            Usually instantiated in ha_joined()
+    @param relation_id: Relation ID of the ha relation
+    @param crm_ocf: Corosync Open Cluster Framework resource agent to use for
+                    DNS HA
+    """
+
+    # Validate the charm environment for DNS HA
+    assert_charm_supports_dns_ha()
+
+    settings = ['os-admin-hostname', 'os-internal-hostname',
+                'os-public-hostname', 'os-access-hostname']
+
+    # Check which DNS settings are set and update dictionaries
+    hostname_group = []
+    for setting in settings:
+        hostname = config(setting)
+        if hostname is None:
+            log('DNS HA: Hostname setting {} is None. Ignoring.'
+                ''.format(setting),
+                DEBUG)
+            continue
+        m = re.search('os-(.+?)-hostname', setting)
+        if m:
+            networkspace = m.group(1)
+        else:
+            msg = ('Unexpected DNS hostname setting: {}. '
+                   'Cannot determine network space name'
+                   ''.format(setting))
+            status_set('blocked', msg)
+            raise DNSHAException(msg)
+
+        hostname_key = 'res_{}_{}_hostname'.format(charm_name(), networkspace)
+        if hostname_key in hostname_group:
+            log('DNS HA: Resource {}: {} already exists in '
+                'hostname group - skipping'.format(hostname_key, hostname),
+                DEBUG)
+            continue
+
+        hostname_group.append(hostname_key)
+        resources[hostname_key] = crm_ocf
+        resource_params[hostname_key] = (
+            'params fqdn="{}" ip_address="{}" '
+            ''.format(hostname, resolve_address(endpoint_type=networkspace,
+                                                override=False)))
+
+    if len(hostname_group) >= 1:
+        log('DNS HA: Hostname group is set with {} as members. '
+            'Informing the ha relation'.format(' '.join(hostname_group)),
+            DEBUG)
+        relation_set(relation_id=relation_id, groups={
+            'grp_{}_hostnames'.format(charm_name()): ' '.join(hostname_group)})
+    else:
+        msg = 'DNS HA: Hostname group has no members.'
+        status_set('blocked', msg)
+        raise DNSHAException(msg)
+
+
+def assert_charm_supports_dns_ha():
+    """Validate prerequisites for DNS HA
+    The MAAS client is only available on Xenial or greater
+    """
+    if lsb_release().get('DISTRIB_RELEASE') < '16.04':
+        msg = ('DNS HA is only supported on 16.04 and greater '
+               'versions of Ubuntu.')
+        status_set('blocked', msg)
+        raise DNSHAException(msg)
+    return True