Auto assign nic for servers context

Servers context now uses nova scenarios's _boot_servers. Enable
auto_assign_nic in servers context could avoid "Multiple possible
networks found" error from Nova.

Change-Id: I15a4f1595344331971078cb1e4f17162e764ac8e
Closes-Bug: #1477583

rally-jobs/nova.yaml

@@ -279,6 +279,8 @@
           image:
               name: {{image_name}}
           servers_per_tenant: 2
+        network:
+          networks_per_tenant: 2
       sla:
         failure_rate:
           max: 0

rally/plugins/openstack/context/nova/servers.py

@@ -30,7 +30,7 @@ LOG = logging.getLogger(__name__)
 class ServerGenerator(context.Context):
     """Context class for adding temporary servers for benchmarks.
 
-        Servers are added for each tenant.
+    Servers are added for each tenant.
     """
 
     CONFIG_SCHEMA = {
@@ -57,19 +57,24 @@ class ServerGenerator(context.Context):
                 "type": "integer",
                 "minimum": 1
             },
+            "auto_assign_nic": {
+                "type": "boolean",
+            }
         },
         "required": ["image", "flavor"],
         "additionalProperties": False
     }
 
     DEFAULT_CONFIG = {
-        "servers_per_tenant": 5
+        "servers_per_tenant": 5,
+        "auto_assign_nic": False
     }
 
     @rutils.log_task_wrapper(LOG.info, _("Enter context: `Servers`"))
     def setup(self):
         image = self.config["image"]
         flavor = self.config["flavor"]
+        auto_nic = self.config["auto_assign_nic"]
         servers_per_tenant = self.config["servers_per_tenant"]
 
         clients = osclients.Clients(self.context["users"][0]["endpoint"])
@@ -78,11 +83,14 @@ class ServerGenerator(context.Context):
         flavor_id = types.FlavorResourceType.transform(clients=clients,
                                                        resource_config=flavor)
 
-        for user, tenant_id in rutils.iterate_per_tenants(
+        for iter_, (user, tenant_id) in enumerate(rutils.iterate_per_tenants(
-                self.context["users"]):
+                self.context["users"])):
             LOG.debug("Booting servers for user tenant %s "
                       % (user["tenant_id"]))
-            nova_scenario = nova_utils.NovaScenario({"user": user})
+            tenant = self.context["tenants"][tenant_id]
+            nova_scenario = nova_utils.NovaScenario({"user": user,
+                                                     "tenant": tenant,
+                                                     "iteration": iter_})
 
             LOG.debug("Calling _boot_servers with image_id=%(image_id)s "
                       "flavor_id=%(flavor_id)s "
@@ -92,7 +100,8 @@ class ServerGenerator(context.Context):
                          "servers_per_tenant": servers_per_tenant})
 
             servers = nova_scenario._boot_servers(image_id, flavor_id,
-                                                  servers_per_tenant)
+                                                  requests=servers_per_tenant,
+                                                  auto_assign_nic=auto_nic)
 
             current_servers = [server.id for server in servers]
 

tests/unit/plugins/openstack/context/nova/test_servers.py

@@ -85,6 +85,7 @@ class ServerGeneratorTestCase(test.ScenarioTestCase):
                     "concurrent": 10,
                 },
                 "servers": {
+                    "auto_assign_nic": True,
                     "servers_per_tenant": 5,
                     "image": {
                         "name": "cirros-0.3.4-x86_64-uec",
@@ -111,6 +112,17 @@ class ServerGeneratorTestCase(test.ScenarioTestCase):
         servers_ctx = servers.ServerGenerator(real_context)
         servers_ctx.setup()
         self.assertEqual(new_context, real_context)
+        image_id = mock_image_resource_type_transform.return_value
+        flavor_id = mock_flavor_resource_type_transform.return_value
+        servers_ctx_config = real_context["config"]["servers"]
+        expected_auto_nic = servers_ctx_config.get("auto_assign_nic", False)
+        expected_requests = servers_ctx_config.get("servers_per_tenant", False)
+        called_times = len(tenants)
+        mock_calls = [mock.call(image_id, flavor_id,
+                                auto_assign_nic=expected_auto_nic,
+                                requests=expected_requests)
+                      for i in range(called_times)]
+        mock_nova_scenario__boot_servers.assert_has_calls(mock_calls)
 
     @mock.patch("%s.servers.osclients" % CTX)
     @mock.patch("%s.servers.resource_manager.cleanup" % CTX)