Heat context code refactor

Heat context code refactor to cater for the evolution of the
Yardstick framework.

At test_case.yaml context segment add "type" to indicate the
context type, see samples/ping-heat-context.yaml for an example.
And the default context type is Heat, so the existing yaml file
do not need to change.

JIRA: YARDSTICK-168

Change-Id: Ida0ce12c17cd9b88d7acfb4c9eb1ac6986394b38
Signed-off-by: QiLiang <liangqi1@huawei.com>

6 files changed, 532 insertions, 469 deletions

diff --git a/yardstick/benchmark/__init__.py b/yardstick/benchmark/__init__.py
index 94357a53a..8b292ac30 100644
--- a/yardstick/benchmark/__init__.py
+++ b/yardstick/benchmark/__init__.py
@@ -9,5 +9,6 @@
 
 import yardstick.common.utils as utils
 
+utils.import_modules_from_package("yardstick.benchmark.contexts")
 utils.import_modules_from_package("yardstick.benchmark.runners")
 utils.import_modules_from_package("yardstick.benchmark.scenarios")
diff --git a/yardstick/benchmark/context/model.py b/yardstick/benchmark/context/model.py
deleted file mode 100644
index 6e754d421..000000000
--- a/yardstick/benchmark/context/model.py
+++ /dev/null
@@ -1,469 +0,0 @@
-##############################################################################
-# Copyright (c) 2015 Ericsson AB and others.
-#
-# All rights reserved. This program and the accompanying materials
-# are made available under the terms of the Apache License, Version 2.0
-# which accompanies this distribution, and is available at
-# http://www.apache.org/licenses/LICENSE-2.0
-##############################################################################
-
-""" Logical model
-
-"""
-
-import sys
-
-from yardstick.orchestrator.heat import HeatTemplate
-
-
-class Object(object):
-    '''Base class for classes in the logical model
-    Contains common attributes and methods
-    '''
-    def __init__(self, name, context):
-        # model identities and reference
-        self.name = name
-        self._context = context
-
-        # stack identities
-        self.stack_name = None
-        self.stack_id = None
-
-    @property
-    def dn(self):
-        '''returns distinguished name for object'''
-        return self.name + "." + self._context.name
-
-
-class PlacementGroup(Object):
-    '''Class that represents a placement group in the logical model
-    Concept comes from the OVF specification. Policy should be one of
-    "availability" or "affinity (there are more but they are not supported)"
-    '''
-    map = {}
-
-    def __init__(self, name, context, policy):
-        if policy not in ["affinity", "availability"]:
-            raise ValueError("placement group '%s', policy '%s' is not valid" %
-                             (name, policy))
-        self.name = name
-        self.members = set()
-        self.stack_name = context.name + "-" + name
-        self.policy = policy
-        PlacementGroup.map[name] = self
-
-    def add_member(self, name):
-        self.members.add(name)
-
-    @staticmethod
-    def get(name):
-        if name in PlacementGroup.map:
-            return PlacementGroup.map[name]
-        else:
-            return None
-
-
-class Router(Object):
-    '''Class that represents a router in the logical model'''
-    def __init__(self, name, network_name, context, external_gateway_info):
-        super(Router, self).__init__(name, context)
-
-        self.stack_name = context.name + "-" + network_name + "-" + self.name
-        self.stack_if_name = self.stack_name + "-if0"
-        self.external_gateway_info = external_gateway_info
-
-
-class Network(Object):
-    '''Class that represents a network in the logical model'''
-    list = []
-
-    def __init__(self, name, context, attrs):
-        super(Network, self).__init__(name, context)
-        self.stack_name = context.name + "-" + self.name
-        self.subnet_stack_name = self.stack_name + "-subnet"
-        self.subnet_cidr = attrs.get('cidr', '10.0.1.0/24')
-        self.router = None
-
-        if "external_network" in attrs:
-            self.router = Router("router", self.name,
-                                 context, attrs["external_network"])
-
-        Network.list.append(self)
-
-    def has_route_to(self, network_name):
-        '''determines if this network has a route to the named network'''
-        if self.router and self.router.external_gateway_info == network_name:
-            return True
-        return False
-
-    @staticmethod
-    def find_by_route_to(external_network):
-        '''finds a network that has a route to the specified network'''
-        for network in Network.list:
-            if network.has_route_to(external_network):
-                return network
-
-    @staticmethod
-    def find_external_network():
-        '''return the name of an external network some network in this
-        context has a route to'''
-        for network in Network.list:
-            if network.router:
-                return network.router.external_gateway_info
-        return None
-
-
-class Server(Object):
-    '''Class that represents a server in the logical model'''
-    list = []
-
-    def __init__(self, name, context, attrs):
-        super(Server, self).__init__(name, context)
-        self.stack_name = self.name + "." + context.name
-        self.keypair_name = context.keypair_name
-        self.secgroup_name = context.secgroup_name
-        self.context = context
-        self.public_ip = None
-        self.private_ip = None
-
-        if attrs is None:
-            attrs = {}
-
-        self.placement_groups = []
-        placement = attrs.get("placement", [])
-        placement = placement if type(placement) is list else [placement]
-        for p in placement:
-            pg = PlacementGroup.get(p)
-            if not pg:
-                raise ValueError("server '%s', placement '%s' is invalid" %
-                                 (name, p))
-            self.placement_groups.append(pg)
-            pg.add_member(self.stack_name)
-
-        self.instances = 1
-        if "instances" in attrs:
-            self.instances = attrs["instances"]
-
-        # dict with key network name, each item is a dict with port name and ip
-        self.ports = {}
-
-        self.floating_ip = None
-        if "floating_ip" in attrs:
-            self.floating_ip = {}
-
-        if self.floating_ip is not None:
-            ext_net = Network.find_external_network()
-            assert ext_net is not None
-            self.floating_ip["external_network"] = ext_net
-
-        self._image = None
-        if "image" in attrs:
-            self._image = attrs["image"]
-
-        self._flavor = None
-        if "flavor" in attrs:
-            self._flavor = attrs["flavor"]
-
-        Server.list.append(self)
-
-    @property
-    def image(self):
-        '''returns a server's image name'''
-        if self._image:
-            return self._image
-        else:
-            return self._context.image
-
-    @property
-    def flavor(self):
-        '''returns a server's flavor name'''
-        if self._flavor:
-            return self._flavor
-        else:
-            return self._context.flavor
-
-    def _add_instance(self, template, server_name, networks, scheduler_hints):
-        '''adds to the template one server and corresponding resources'''
-        port_name_list = []
-        for network in networks:
-            port_name = server_name + "-" + network.name + "-port"
-            self.ports[network.name] = {"stack_name": port_name}
-            template.add_port(port_name, network.stack_name,
-                              network.subnet_stack_name,
-                              sec_group_id=self.secgroup_name)
-            port_name_list.append(port_name)
-
-            if self.floating_ip:
-                external_network = self.floating_ip["external_network"]
-                if network.has_route_to(external_network):
-                    self.floating_ip["stack_name"] = server_name + "-fip"
-                    template.add_floating_ip(self.floating_ip["stack_name"],
-                                             external_network,
-                                             port_name,
-                                             network.router.stack_if_name,
-                                             self.secgroup_name)
-
-        template.add_server(server_name, self.image, self.flavor,
-                            ports=port_name_list,
-                            key_name=self.keypair_name,
-                            scheduler_hints=scheduler_hints)
-
-    def add_to_template(self, template, networks, scheduler_hints=None):
-        '''adds to the template one or more servers (instances)'''
-        if self.instances == 1:
-            server_name = self.stack_name
-            self._add_instance(template, server_name, networks,
-                               scheduler_hints=scheduler_hints)
-        else:
-            # TODO(hafe) fix or remove, no test/sample for this
-            for i in range(self.instances):
-                server_name = "%s-%d" % (self.stack_name, i)
-                self._add_instance(template, server_name, networks,
-                                   scheduler_hints=scheduler_hints)
-
-
-def update_scheduler_hints(scheduler_hints, added_servers, placement_group):
-    ''' update scheduler hints from server's placement configuration
-    TODO: this code is openstack specific and should move somewhere else
-    '''
-    if placement_group.policy == "affinity":
-        if "same_host" in scheduler_hints:
-            host_list = scheduler_hints["same_host"]
-        else:
-            host_list = scheduler_hints["same_host"] = []
-    else:
-        if "different_host" in scheduler_hints:
-            host_list = scheduler_hints["different_host"]
-        else:
-            host_list = scheduler_hints["different_host"] = []
-
-    for name in added_servers:
-        if name in placement_group.members:
-            host_list.append({'get_resource': name})
-
-
-class Context(object):
-    '''Class that represents a context in the logical model'''
-    list = []
-
-    def __init__(self):
-        self.name = None
-        self.stack = None
-        self.networks = []
-        self.servers = []
-        self.placement_groups = []
-        self.keypair_name = None
-        self.secgroup_name = None
-        self._server_map = {}
-        self._image = None
-        self._flavor = None
-        self._user = None
-        self.template_file = None
-        self.heat_parameters = None
-        Context.list.append(self)
-
-    def init(self, attrs):
-        '''initializes itself from the supplied arguments'''
-        self.name = attrs["name"]
-
-        if "user" in attrs:
-            self._user = attrs["user"]
-
-        if "heat_template" in attrs:
-            self.template_file = attrs["heat_template"]
-            self.heat_parameters = attrs.get("heat_parameters", None)
-            return
-
-        self.keypair_name = self.name + "-key"
-        self.secgroup_name = self.name + "-secgroup"
-
-        if "image" in attrs:
-            self._image = attrs["image"]
-
-        if "flavor" in attrs:
-            self._flavor = attrs["flavor"]
-
-        if "placement_groups" in attrs:
-            for name, pgattrs in attrs["placement_groups"].items():
-                pg = PlacementGroup(name, self, pgattrs["policy"])
-                self.placement_groups.append(pg)
-
-        for name, netattrs in attrs["networks"].items():
-            network = Network(name, self, netattrs)
-            self.networks.append(network)
-
-        for name, serverattrs in attrs["servers"].items():
-            server = Server(name, self, serverattrs)
-            self.servers.append(server)
-            self._server_map[server.dn] = server
-
-    @property
-    def image(self):
-        '''returns application's default image name'''
-        return self._image
-
-    @property
-    def flavor(self):
-        '''returns application's default flavor name'''
-        return self._flavor
-
-    @property
-    def user(self):
-        '''return login user name corresponding to image'''
-        return self._user
-
-    def _add_resources_to_template(self, template):
-        '''add to the template the resources represented by this context'''
-        template.add_keypair(self.keypair_name)
-        template.add_security_group(self.secgroup_name)
-
-        for network in self.networks:
-            template.add_network(network.stack_name)
-            template.add_subnet(network.subnet_stack_name, network.stack_name,
-                                network.subnet_cidr)
-
-            if network.router:
-                template.add_router(network.router.stack_name,
-                                    network.router.external_gateway_info,
-                                    network.subnet_stack_name)
-                template.add_router_interface(network.router.stack_if_name,
-                                              network.router.stack_name,
-                                              network.subnet_stack_name)
-
-        # create a list of servers sorted by increasing no of placement groups
-        list_of_servers = sorted(self.servers,
-                                 key=lambda s: len(s.placement_groups))
-
-        #
-        # add servers with scheduler hints derived from placement groups
-        #
-
-        # create list of servers with availability policy
-        availability_servers = []
-        for server in list_of_servers:
-            for pg in server.placement_groups:
-                if pg.policy == "availability":
-                    availability_servers.append(server)
-                    break
-
-        # add servers with availability policy
-        added_servers = []
-        for server in availability_servers:
-            scheduler_hints = {}
-            for pg in server.placement_groups:
-                update_scheduler_hints(scheduler_hints, added_servers, pg)
-            server.add_to_template(template, self.networks, scheduler_hints)
-            added_servers.append(server.stack_name)
-
-        # create list of servers with affinity policy
-        affinity_servers = []
-        for server in list_of_servers:
-            for pg in server.placement_groups:
-                if pg.policy == "affinity":
-                    affinity_servers.append(server)
-                    break
-
-        # add servers with affinity policy
-        for server in affinity_servers:
-            if server.stack_name in added_servers:
-                continue
-            scheduler_hints = {}
-            for pg in server.placement_groups:
-                update_scheduler_hints(scheduler_hints, added_servers, pg)
-            server.add_to_template(template, self.networks, scheduler_hints)
-            added_servers.append(server.stack_name)
-
-        # add remaining servers with no placement group configured
-        for server in list_of_servers:
-            if len(server.placement_groups) == 0:
-                server.add_to_template(template, self.networks, {})
-
-    def deploy(self):
-        '''deploys template into a stack using cloud'''
-        print "Deploying context '%s'" % self.name
-
-        heat_template = HeatTemplate(self.name, self.template_file,
-                                     self.heat_parameters)
-
-        if self.template_file is None:
-            self._add_resources_to_template(heat_template)
-
-        try:
-            self.stack = heat_template.create()
-        except KeyboardInterrupt:
-            sys.exit("\nStack create interrupted")
-        except RuntimeError as err:
-            sys.exit("error: failed to deploy stack: '%s'" % err.args)
-        except Exception as err:
-            sys.exit("error: failed to deploy stack: '%s'" % err)
-
-        # copy some vital stack output into server objects
-        for server in self.servers:
-            if len(server.ports) > 0:
-                # TODO(hafe) can only handle one internal network for now
-                port = server.ports.values()[0]
-                server.private_ip = self.stack.outputs[port["stack_name"]]
-
-            if server.floating_ip:
-                server.public_ip = \
-                    self.stack.outputs[server.floating_ip["stack_name"]]
-
-        print "Context '%s' deployed" % self.name
-
-    def undeploy(self):
-        '''undeploys stack from cloud'''
-        if self.stack:
-            print "Undeploying context '%s'" % self.name
-            self.stack.delete()
-            self.stack = None
-            print "Context '%s' undeployed" % self.name
-
-    @staticmethod
-    def get_server_by_name(dn):
-        '''lookup server object by DN
-
-        dn is a distinguished name including the context name'''
-        if "." not in dn:
-            raise ValueError("dn '%s' is malformed" % dn)
-
-        for context in Context.list:
-            if dn in context._server_map:
-                return context._server_map[dn]
-
-        return None
-
-    @staticmethod
-    def get_context_by_name(name):
-        for context in Context.list:
-            if name == context.name:
-                return context
-        return None
-
-    @staticmethod
-    def get_server(attr_name):
-        '''lookup server object by name from context
-        attr_name: either a name for a server created by yardstick or a dict
-        with attribute name mapping when using external heat templates
-        '''
-        if type(attr_name) is dict:
-            cname = attr_name["name"].split(".")[1]
-            context = Context.get_context_by_name(cname)
-            if context is None:
-                raise ValueError("context not found for server '%s'" %
-                                 attr_name["name"])
-
-            public_ip = None
-            private_ip = None
-            if "public_ip_attr" in attr_name:
-                public_ip = context.stack.outputs[attr_name["public_ip_attr"]]
-            if "private_ip_attr" in attr_name:
-                private_ip = context.stack.outputs[
-                    attr_name["private_ip_attr"]]
-
-            # Create a dummy server instance for holding the *_ip attributes
-            server = Server(attr_name["name"].split(".")[0], context, {})
-            server.public_ip = public_ip
-            server.private_ip = private_ip
-            return server
-        else:
-            return Context.get_server_by_name(attr_name)
diff --git a/yardstick/benchmark/context/__init__.py b/yardstick/benchmark/contexts/__init__.py
index e69de29bb..e69de29bb 100644
--- a/yardstick/benchmark/context/__init__.py
+++ b/yardstick/benchmark/contexts/__init__.py
diff --git a/yardstick/benchmark/contexts/base.py b/yardstick/benchmark/contexts/base.py
new file mode 100644
index 000000000..ae860accd
--- /dev/null
+++ b/yardstick/benchmark/contexts/base.py
@@ -0,0 +1,70 @@
+##############################################################################
+# Copyright (c) 2015 Huawei Technologies Co.,Ltd and others.
+#
+# All rights reserved. This program and the accompanying materials
+# are made available under the terms of the Apache License, Version 2.0
+# which accompanies this distribution, and is available at
+# http://www.apache.org/licenses/LICENSE-2.0
+##############################################################################
+import abc
+import six
+
+import yardstick.common.utils as utils
+
+
+@six.add_metaclass(abc.ABCMeta)
+class Context(object):
+    '''Class that represents a context in the logical model'''
+    list = []
+
+    def __init__(self):
+        Context.list.append(self)
+
+    @abc.abstractmethod
+    def init(self, attrs):
+        "Initiate context."
+
+    @staticmethod
+    def get_cls(context_type):
+        '''Return class of specified type.'''
+        for context in utils.itersubclasses(Context):
+            if context_type == context.__context_type__:
+                return context
+        raise RuntimeError("No such context_type %s" % context_type)
+
+    @staticmethod
+    def get(context_type):
+        """Returns instance of a context for context type.
+        """
+        return Context.get_cls(context_type)()
+
+    @abc.abstractmethod
+    def deploy(self):
+        '''Deploy context.'''
+
+    @abc.abstractmethod
+    def undeploy(self):
+        '''Undeploy context.'''
+
+    @abc.abstractmethod
+    def _get_server(self, attr_name):
+        '''get server object by name from context
+        '''
+
+    @staticmethod
+    def get_server(attr_name):
+        '''lookup server object by name from context
+        attr_name: either a name for a server created by yardstick or a dict
+        with attribute name mapping when using external heat templates
+        '''
+        server = None
+        for context in Context.list:
+            server = context._get_server(attr_name)
+            if server is not None:
+                break
+
+        if server is None:
+            raise ValueError("context not found for server '%s'" %
+                             attr_name["name"])
+
+        return server
diff --git a/yardstick/benchmark/contexts/heat.py b/yardstick/benchmark/contexts/heat.py
new file mode 100644
index 000000000..9cf29981b
--- /dev/null
+++ b/yardstick/benchmark/contexts/heat.py
@@ -0,0 +1,223 @@
+##############################################################################
+# Copyright (c) 2015 Ericsson AB and others.
+#
+# All rights reserved. This program and the accompanying materials
+# are made available under the terms of the Apache License, Version 2.0
+# which accompanies this distribution, and is available at
+# http://www.apache.org/licenses/LICENSE-2.0
+##############################################################################
+
+import sys
+
+from yardstick.benchmark.contexts.base import Context
+from yardstick.benchmark.contexts.model import Server
+from yardstick.benchmark.contexts.model import PlacementGroup
+from yardstick.benchmark.contexts.model import Network
+from yardstick.benchmark.contexts.model import update_scheduler_hints
+from yardstick.orchestrator.heat import HeatTemplate
+
+
+class HeatContext(Context):
+    '''Class that represents a context in the logical model'''
+
+    __context_type__ = "Heat"
+
+    def __init__(self):
+        self.name = None
+        self.stack = None
+        self.networks = []
+        self.servers = []
+        self.placement_groups = []
+        self.keypair_name = None
+        self.secgroup_name = None
+        self._server_map = {}
+        self._image = None
+        self._flavor = None
+        self._user = None
+        self.template_file = None
+        self.heat_parameters = None
+        super(self.__class__, self).__init__()
+
+    def init(self, attrs):
+        '''initializes itself from the supplied arguments'''
+        self.name = attrs["name"]
+
+        if "user" in attrs:
+            self._user = attrs["user"]
+
+        if "heat_template" in attrs:
+            self.template_file = attrs["heat_template"]
+            self.heat_parameters = attrs.get("heat_parameters", None)
+            return
+
+        self.keypair_name = self.name + "-key"
+        self.secgroup_name = self.name + "-secgroup"
+
+        if "image" in attrs:
+            self._image = attrs["image"]
+
+        if "flavor" in attrs:
+            self._flavor = attrs["flavor"]
+
+        if "placement_groups" in attrs:
+            for name, pgattrs in attrs["placement_groups"].items():
+                pg = PlacementGroup(name, self, pgattrs["policy"])
+                self.placement_groups.append(pg)
+
+        for name, netattrs in attrs["networks"].items():
+            network = Network(name, self, netattrs)
+            self.networks.append(network)
+
+        for name, serverattrs in attrs["servers"].items():
+            server = Server(name, self, serverattrs)
+            self.servers.append(server)
+            self._server_map[server.dn] = server
+
+    @property
+    def image(self):
+        '''returns application's default image name'''
+        return self._image
+
+    @property
+    def flavor(self):
+        '''returns application's default flavor name'''
+        return self._flavor
+
+    @property
+    def user(self):
+        '''return login user name corresponding to image'''
+        return self._user
+
+    def _add_resources_to_template(self, template):
+        '''add to the template the resources represented by this context'''
+        template.add_keypair(self.keypair_name)
+        template.add_security_group(self.secgroup_name)
+
+        for network in self.networks:
+            template.add_network(network.stack_name)
+            template.add_subnet(network.subnet_stack_name, network.stack_name,
+                                network.subnet_cidr)
+
+            if network.router:
+                template.add_router(network.router.stack_name,
+                                    network.router.external_gateway_info,
+                                    network.subnet_stack_name)
+                template.add_router_interface(network.router.stack_if_name,
+                                              network.router.stack_name,
+                                              network.subnet_stack_name)
+
+        # create a list of servers sorted by increasing no of placement groups
+        list_of_servers = sorted(self.servers,
+                                 key=lambda s: len(s.placement_groups))
+
+        #
+        # add servers with scheduler hints derived from placement groups
+        #
+
+        # create list of servers with availability policy
+        availability_servers = []
+        for server in list_of_servers:
+            for pg in server.placement_groups:
+                if pg.policy == "availability":
+                    availability_servers.append(server)
+                    break
+
+        # add servers with availability policy
+        added_servers = []
+        for server in availability_servers:
+            scheduler_hints = {}
+            for pg in server.placement_groups:
+                update_scheduler_hints(scheduler_hints, added_servers, pg)
+            server.add_to_template(template, self.networks, scheduler_hints)
+            added_servers.append(server.stack_name)
+
+        # create list of servers with affinity policy
+        affinity_servers = []
+        for server in list_of_servers:
+            for pg in server.placement_groups:
+                if pg.policy == "affinity":
+                    affinity_servers.append(server)
+                    break
+
+        # add servers with affinity policy
+        for server in affinity_servers:
+            if server.stack_name in added_servers:
+                continue
+            scheduler_hints = {}
+            for pg in server.placement_groups:
+                update_scheduler_hints(scheduler_hints, added_servers, pg)
+            server.add_to_template(template, self.networks, scheduler_hints)
+            added_servers.append(server.stack_name)
+
+        # add remaining servers with no placement group configured
+        for server in list_of_servers:
+            if len(server.placement_groups) == 0:
+                server.add_to_template(template, self.networks, {})
+
+    def deploy(self):
+        '''deploys template into a stack using cloud'''
+        print "Deploying context '%s'" % self.name
+
+        heat_template = HeatTemplate(self.name, self.template_file,
+                                     self.heat_parameters)
+
+        if self.template_file is None:
+            self._add_resources_to_template(heat_template)
+
+        try:
+            self.stack = heat_template.create()
+        except KeyboardInterrupt:
+            sys.exit("\nStack create interrupted")
+        except RuntimeError as err:
+            sys.exit("error: failed to deploy stack: '%s'" % err.args)
+        except Exception as err:
+            sys.exit("error: failed to deploy stack: '%s'" % err)
+
+        # copy some vital stack output into server objects
+        for server in self.servers:
+            if len(server.ports) > 0:
+                # TODO(hafe) can only handle one internal network for now
+                port = server.ports.values()[0]
+                server.private_ip = self.stack.outputs[port["stack_name"]]
+
+            if server.floating_ip:
+                server.public_ip = \
+                    self.stack.outputs[server.floating_ip["stack_name"]]
+
+        print "Context '%s' deployed" % self.name
+
+    def undeploy(self):
+        '''undeploys stack from cloud'''
+        if self.stack:
+            print "Undeploying context '%s'" % self.name
+            self.stack.delete()
+            self.stack = None
+            print "Context '%s' undeployed" % self.name
+
+    def _get_server(self, attr_name):
+        '''lookup server object by name from context
+        attr_name: either a name for a server created by yardstick or a dict
+        with attribute name mapping when using external heat templates
+        '''
+        if type(attr_name) is dict:
+            cname = attr_name["name"].split(".")[1]
+            if cname != self.name:
+                return None
+
+            public_ip = None
+            private_ip = None
+            if "public_ip_attr" in attr_name:
+                public_ip = self.stack.outputs[attr_name["public_ip_attr"]]
+            if "private_ip_attr" in attr_name:
+                private_ip = self.stack.outputs[
+                    attr_name["private_ip_attr"]]
+
+            # Create a dummy server instance for holding the *_ip attributes
+            server = Server(attr_name["name"].split(".")[0], self, {})
+            server.public_ip = public_ip
+            server.private_ip = private_ip
+            return server
+        else:
+            if attr_name not in self._server_map:
+                return None
+            return self._server_map[attr_name]
diff --git a/yardstick/benchmark/contexts/model.py b/yardstick/benchmark/contexts/model.py
new file mode 100644
index 000000000..91020b92f
--- /dev/null
+++ b/yardstick/benchmark/contexts/model.py
@@ -0,0 +1,238 @@
+##############################################################################
+# Copyright (c) 2015 Ericsson AB and others.
+#
+# All rights reserved. This program and the accompanying materials
+# are made available under the terms of the Apache License, Version 2.0
+# which accompanies this distribution, and is available at
+# http://www.apache.org/licenses/LICENSE-2.0
+##############################################################################
+
+""" Logical model
+
+"""
+
+
+class Object(object):
+    '''Base class for classes in the logical model
+    Contains common attributes and methods
+    '''
+    def __init__(self, name, context):
+        # model identities and reference
+        self.name = name
+        self._context = context
+
+        # stack identities
+        self.stack_name = None
+        self.stack_id = None
+
+    @property
+    def dn(self):
+        '''returns distinguished name for object'''
+        return self.name + "." + self._context.name
+
+
+class PlacementGroup(Object):
+    '''Class that represents a placement group in the logical model
+    Concept comes from the OVF specification. Policy should be one of
+    "availability" or "affinity (there are more but they are not supported)"
+    '''
+    map = {}
+
+    def __init__(self, name, context, policy):
+        if policy not in ["affinity", "availability"]:
+            raise ValueError("placement group '%s', policy '%s' is not valid" %
+                             (name, policy))
+        self.name = name
+        self.members = set()
+        self.stack_name = context.name + "-" + name
+        self.policy = policy
+        PlacementGroup.map[name] = self
+
+    def add_member(self, name):
+        self.members.add(name)
+
+    @staticmethod
+    def get(name):
+        if name in PlacementGroup.map:
+            return PlacementGroup.map[name]
+        else:
+            return None
+
+
+class Router(Object):
+    '''Class that represents a router in the logical model'''
+    def __init__(self, name, network_name, context, external_gateway_info):
+        super(self.__class__, self).__init__(name, context)
+
+        self.stack_name = context.name + "-" + network_name + "-" + self.name
+        self.stack_if_name = self.stack_name + "-if0"
+        self.external_gateway_info = external_gateway_info
+
+
+class Network(Object):
+    '''Class that represents a network in the logical model'''
+    list = []
+
+    def __init__(self, name, context, attrs):
+        super(self.__class__, self).__init__(name, context)
+        self.stack_name = context.name + "-" + self.name
+        self.subnet_stack_name = self.stack_name + "-subnet"
+        self.subnet_cidr = attrs.get('cidr', '10.0.1.0/24')
+        self.router = None
+
+        if "external_network" in attrs:
+            self.router = Router("router", self.name,
+                                 context, attrs["external_network"])
+
+        Network.list.append(self)
+
+    def has_route_to(self, network_name):
+        '''determines if this network has a route to the named network'''
+        if self.router and self.router.external_gateway_info == network_name:
+            return True
+        return False
+
+    @staticmethod
+    def find_by_route_to(external_network):
+        '''finds a network that has a route to the specified network'''
+        for network in Network.list:
+            if network.has_route_to(external_network):
+                return network
+
+    @staticmethod
+    def find_external_network():
+        '''return the name of an external network some network in this
+        context has a route to'''
+        for network in Network.list:
+            if network.router:
+                return network.router.external_gateway_info
+        return None
+
+
+class Server(Object):
+    '''Class that represents a server in the logical model'''
+    list = []
+
+    def __init__(self, name, context, attrs):
+        super(self.__class__, self).__init__(name, context)
+        self.stack_name = self.name + "." + context.name
+        self.keypair_name = context.keypair_name
+        self.secgroup_name = context.secgroup_name
+        self.context = context
+        self.public_ip = None
+        self.private_ip = None
+
+        if attrs is None:
+            attrs = {}
+
+        self.placement_groups = []
+        placement = attrs.get("placement", [])
+        placement = placement if type(placement) is list else [placement]
+        for p in placement:
+            pg = PlacementGroup.get(p)
+            if not pg:
+                raise ValueError("server '%s', placement '%s' is invalid" %
+                                 (name, p))
+            self.placement_groups.append(pg)
+            pg.add_member(self.stack_name)
+
+        self.instances = 1
+        if "instances" in attrs:
+            self.instances = attrs["instances"]
+
+        # dict with key network name, each item is a dict with port name and ip
+        self.ports = {}
+
+        self.floating_ip = None
+        if "floating_ip" in attrs:
+            self.floating_ip = {}
+
+        if self.floating_ip is not None:
+            ext_net = Network.find_external_network()
+            assert ext_net is not None
+            self.floating_ip["external_network"] = ext_net
+
+        self._image = None
+        if "image" in attrs:
+            self._image = attrs["image"]
+
+        self._flavor = None
+        if "flavor" in attrs:
+            self._flavor = attrs["flavor"]
+
+        Server.list.append(self)
+
+    @property
+    def image(self):
+        '''returns a server's image name'''
+        if self._image:
+            return self._image
+        else:
+            return self._context.image
+
+    @property
+    def flavor(self):
+        '''returns a server's flavor name'''
+        if self._flavor:
+            return self._flavor
+        else:
+            return self._context.flavor
+
+    def _add_instance(self, template, server_name, networks, scheduler_hints):
+        '''adds to the template one server and corresponding resources'''
+        port_name_list = []
+        for network in networks:
+            port_name = server_name + "-" + network.name + "-port"
+            self.ports[network.name] = {"stack_name": port_name}
+            template.add_port(port_name, network.stack_name,
+                              network.subnet_stack_name,
+                              sec_group_id=self.secgroup_name)
+            port_name_list.append(port_name)
+
+            if self.floating_ip:
+                external_network = self.floating_ip["external_network"]
+                if network.has_route_to(external_network):
+                    self.floating_ip["stack_name"] = server_name + "-fip"
+                    template.add_floating_ip(self.floating_ip["stack_name"],
+                                             external_network,
+                                             port_name,
+                                             network.router.stack_if_name,
+                                             self.secgroup_name)
+
+        template.add_server(server_name, self.image, self.flavor,
+                            ports=port_name_list,
+                            key_name=self.keypair_name,
+                            scheduler_hints=scheduler_hints)
+
+    def add_to_template(self, template, networks, scheduler_hints=None):
+        '''adds to the template one or more servers (instances)'''
+        if self.instances == 1:
+            server_name = self.stack_name
+            self._add_instance(template, server_name, networks,
+                               scheduler_hints=scheduler_hints)
+        else:
+            # TODO(hafe) fix or remove, no test/sample for this
+            for i in range(self.instances):
+                server_name = "%s-%d" % (self.stack_name, i)
+                self._add_instance(template, server_name, networks,
+                                   scheduler_hints=scheduler_hints)
+
+
+def update_scheduler_hints(scheduler_hints, added_servers, placement_group):
+    ''' update scheduler hints from server's placement configuration
+    TODO: this code is openstack specific and should move somewhere else
+    '''
+    if placement_group.policy == "affinity":
+        if "same_host" in scheduler_hints:
+            host_list = scheduler_hints["same_host"]
+        else:
+            host_list = scheduler_hints["same_host"] = []
+    else:
+        if "different_host" in scheduler_hints:
+            host_list = scheduler_hints["different_host"]
+        else:
+            host_list = scheduler_hints["different_host"] = []
+
+    for name in added_servers:
+        if name in placement_group.members:
+            host_list.append({'get_resource': name})