L3 agent: use run_immediately parameter to sync after start

Explicit call to periodic resync after start may lead to
double syncing. See bug for details.

Closes-Bug: #1505282
Change-Id: Ib5e481d579039b2c3e87d4f12cad1241d02fe060

neutron/agent/l3/agent.py

@@ -524,7 +524,7 @@ class L3NATAgent(firewall_l3_agent.FWaaSL3AgentRpcCallback,
     # NOTE(kevinbenton): this is set to 1 second because the actual interval
     # is controlled by a FixedIntervalLoopingCall in neutron/service.py that
     # is responsible for task execution.
-    @periodic_task.periodic_task(spacing=1)
+    @periodic_task.periodic_task(spacing=1, run_immediately=True)
     def periodic_sync_routers_task(self, context):
         self.process_services_sync(context)
         if not self.fullsync:
@@ -597,8 +597,6 @@ class L3NATAgent(firewall_l3_agent.FWaaSL3AgentRpcCallback,
         # L3NATAgent.
         eventlet.spawn_n(self._process_routers_loop)
         LOG.info(_LI("L3 agent started"))
-        # When L3 agent is ready, we immediately do a full sync
-        self.periodic_sync_routers_task(self.context)
 
     def create_pd_router_update(self):
         router_id = None
@@ -678,9 +676,6 @@ class L3NATAgentWithStateReport(L3NATAgent):
         # Do the report state before we do the first full sync.
         self._report_state()
 
-        # When L3 agent is ready, we immediately do a full sync
-        self.periodic_sync_routers_task(self.context)
-
         self.pd.after_start()
 
     def agent_updated(self, context, payload):

neutron/tests/unit/agent/l3/test_agent.py

@@ -186,14 +186,6 @@ class TestBasicRouterOperations(BasicRouterOperationsFramework):
                           agent.context)
         self.assertTrue(agent.fullsync)
 
-    def test_l3_initial_full_sync_done(self):
-        with mock.patch.object(l3_agent.L3NATAgent,
-                               'periodic_sync_routers_task') as router_sync:
-            with mock.patch.object(eventlet, 'spawn_n'):
-                agent = l3_agent.L3NATAgent(HOSTNAME, self.conf)
-                agent.after_start()
-                router_sync.assert_called_once_with(agent.context)
-
     def test_l3_initial_report_state_done(self):
         with mock.patch.object(l3_agent.L3NATAgentWithStateReport,
                                'periodic_sync_routers_task'),\