Merge "Fixes race condition and boosts the scheduling performance" into stable/juno

neutron/db/l3_agentschedulers_db.py

@@ -378,6 +378,23 @@ class L3AgentSchedulerDbMixin(l3agentscheduler.L3AgentSchedulerPluginBase,
             return False
 
         core_plugin = manager.NeutronManager.get_plugin()
+        # NOTE(swami):Before checking for existence of dvr
+        # serviceable ports on the host managed by the l3
+        # agent, let's verify if at least one subnet has
+        # dhcp enabled. If so, then the host will have a
+        # dvr serviceable port, which is in fact the DHCP
+        # port.
+        # This optimization is valid assuming that the L3
+        # DVR_SNAT node will be the one hosting the DHCP
+        # Agent.
+        agent_conf = self.get_configuration_dict(l3_agent)
+        agent_mode = agent_conf.get('agent_mode', 'legacy')
+
+        for subnet_id in subnet_ids:
+            subnet_dict = core_plugin.get_subnet(context, subnet_id)
+            if subnet_dict['enable_dhcp'] and agent_mode == 'dvr_snat':
+                return True
+
         filter = {'fixed_ips': {'subnet_id': subnet_ids}}
         ports = core_plugin.get_ports(context, filters=filter)
         for port in ports:

neutron/tests/unit/test_l3_schedulers.py

@@ -661,6 +661,29 @@ class L3SchedulerTestBaseMixin(object):
                                                     l3_agent, router['id'])
             self.assertFalse(val)
 
+    def test_check_ports_exist_on_l3agent_with_dhcp_enabled_subnets(self):
+        self._register_l3_dvr_agents()
+        router = self._make_router(self.fmt,
+                                   tenant_id=str(uuid.uuid4()),
+                                   name='r2')
+        router['external_gateway_info'] = None
+        router['id'] = str(uuid.uuid4())
+        router['distributed'] = True
+
+        agent_list = [self.l3_dvr_snat_agent]
+        subnet = {'id': str(uuid.uuid4()),
+                  'enable_dhcp': True}
+
+        self.get_subnet_ids_on_router = mock.Mock(
+            return_value=[subnet['id']])
+
+        self.plugin.get_subnet = mock.Mock(return_value=subnet)
+        self.plugin.get_ports = mock.Mock()
+        val = self.check_ports_exist_on_l3agent(
+            self.adminContext, agent_list[0], router['id'])
+        self.assertTrue(val)
+        self.assertFalse(self.plugin.get_ports.called)
+
     def test_check_ports_exist_on_l3agent_if_no_subnets_then_return(self):
         l3_agent, router = self._prepare_check_ports_exist_tests()
         with mock.patch.object(manager.NeutronManager,
@@ -678,7 +701,9 @@ class L3SchedulerTestBaseMixin(object):
                                'get_plugin') as getp:
             getp.return_value = self.plugin
             # no matching subnet
-            self.get_subnet_ids_on_router.return_value = [str(uuid.uuid4())]
+            subnet = {'id': str(uuid.uuid4()), 'enable_dhcp': False}
+            self.get_subnet_ids_on_router.return_value = [subnet['id']]
+            self.plugin.get_subnet = mock.Mock(return_value=subnet)
             val = self.check_ports_exist_on_l3agent(self.adminContext,
                                                     l3_agent, router['id'])
             self.assertFalse(val)
@@ -693,9 +718,12 @@ class L3SchedulerTestBaseMixin(object):
                     'binding:host_id': HOST,
                     'device_owner': 'compute:',
                     'id': 1234}
+            subnet = {'id': str(uuid.uuid4()),
+                      'enable_dhcp': False}
             self.plugin.get_ports.return_value = [port]
             self.get_subnet_ids_on_router = mock.Mock(
                 return_value=[port['subnet_id']])
+            self.plugin.get_subnet = mock.Mock(return_value=subnet)
             val = self.check_ports_exist_on_l3agent(self.adminContext,
                                                     l3_agent, router['id'])
             self.assertTrue(val)