Fix controller worker graceful shutdown

Fix an issue that prevents graceful shutdown of controller workers.

cotyledon.Service.terminate function is by definition the graceful
termination function and doesn't have any 'graceful' optional boolean
argument (https://cotyledon.readthedocs.io/en/latest/api.html).

Because of this error, message_listener.wait() was never called in the
consumers' termination functions, so flows could be interrupted before
completion and could leave resources such as load balancer in a
PENDING_* provisioning state.

By default cotyledon.Service terminates the server after a timeout if
the worker could not shutdown itself gracefully. The default value
for the timeout is 300 seconds (set in devstack plugin) and can be
overriden using the graceful_shutdown_timeout setting in octavia.conf
The default value will be updated to a lower value when work on
persistant taskflow will be merged.

Story: 2006603
Task: 36770

Change-Id: I3f776bd018246897c9a889699a2d0ecbbfbb7098

devstack/plugin.sh

@@ -385,6 +385,11 @@ function octavia_configure {
         iniset $OCTAVIA_CONF api_settings bind_port ${OCTAVIA_HA_PORT}
         iniset $OCTAVIA_CONF api_settings bind_host 0.0.0.0
     fi
+
+    # set default graceful_shutdown_timeout to 300 sec (5 minutes)
+    # TODO(gthiemonge) update this value after persistant taskflow commits are
+    # merged
+    iniset $OCTAVIA_CONF DEFAULT graceful_shutdown_timeout 300
 }
 
 function create_mgmt_network_interface {

doc/source/configuration/configref.rst

@@ -26,3 +26,4 @@ Octavia Configuration Options
     oslo.db
     oslo.log
     oslo.messaging
+    cotyledon

etc/octavia.conf

@@ -16,6 +16,9 @@
 #   transport_url = rabbit://<user>:<pass>@server01,<user>:<pass>@server02/<vhost>
 # transport_url =
 
+# How long in seconds to wait for octavia worker to exit before killing them.
+# graceful_shutdown_timeout = 60
+
 [api_settings]
 # bind_host = 127.0.0.1
 # bind_port = 9876

octavia/controller/queue/v1/consumer.py

@@ -46,11 +46,11 @@ class ConsumerService(cotyledon.Service):
         )
         self.message_listener.start()
 
-    def terminate(self, graceful=False):
+    def terminate(self):
         if self.message_listener:
             LOG.info('Stopping consumer...')
             self.message_listener.stop()
-            if graceful:
+
             LOG.info('Consumer successfully stopped.  Waiting for final '
                      'messages to be processed...')
             self.message_listener.wait()

octavia/controller/queue/v2/consumer.py

@@ -47,11 +47,11 @@ class ConsumerService(cotyledon.Service):
         )
         self.message_listener.start()
 
-    def terminate(self, graceful=False):
+    def terminate(self):
         if self.message_listener:
             LOG.info('Stopping V2 consumer...')
             self.message_listener.stop()
-            if graceful:
+
             LOG.info('V2 Consumer successfully stopped.  Waiting for '
                      'final messages to be processed...')
             self.message_listener.wait()

octavia/tests/unit/controller/queue/v1/test_consumer.py

@@ -58,15 +58,4 @@ class TestConsumer(base.TestRpc):
         cons.run()
         cons.terminate()
         mock_rpc_server_rv.stop.assert_called_once_with()
-        self.assertFalse(mock_rpc_server_rv.wait.called)
-
-    @mock.patch.object(messaging, 'get_rpc_server')
-    def test_consumer_graceful_terminate(self, mock_rpc_server):
-        mock_rpc_server_rv = mock.Mock()
-        mock_rpc_server.return_value = mock_rpc_server_rv
-
-        cons = consumer.ConsumerService(1, self.conf)
-        cons.run()
-        cons.terminate(graceful=True)
-        mock_rpc_server_rv.stop.assert_called_once_with()
         mock_rpc_server_rv.wait.assert_called_once_with()

octavia/tests/unit/controller/queue/v2/test_consumer.py

@@ -58,15 +58,4 @@ class TestConsumer(base.TestRpc):
         cons.run()
         cons.terminate()
         mock_rpc_server_rv.stop.assert_called_once_with()
-        self.assertFalse(mock_rpc_server_rv.wait.called)
-
-    @mock.patch.object(messaging, 'get_rpc_server')
-    def test_consumer_graceful_terminate(self, mock_rpc_server):
-        mock_rpc_server_rv = mock.Mock()
-        mock_rpc_server.return_value = mock_rpc_server_rv
-
-        cons = consumer.ConsumerService(1, self.conf)
-        cons.run()
-        cons.terminate(graceful=True)
-        mock_rpc_server_rv.stop.assert_called_once_with()
         mock_rpc_server_rv.wait.assert_called_once_with()

releasenotes/notes/fix-worker-graceful-shutdown-c44b6797637aa1b3.yaml

@@ -0,0 +1,9 @@
+---
+fixes:
+  - |
+    Fix a bug that could interrupt resource creation when performing a graceful
+    shutdown of the controller worker and leave resources in a
+    PENDING_CREATE/PENDING_UPDATE/PENDING_DELETE provisioning status. If the
+    duration of an Octavia flow is greater than the 'graceful_shutdown_timeout'
+    configuration value, stopping the Octavia worker can still interrupt the
+    creation of resources.

tox.ini

@@ -127,7 +127,8 @@ commands =
          --namespace oslo.db \
          --namespace oslo.log \
          --namespace oslo.messaging \
-         --namespace keystonemiddleware.auth_token
+         --namespace keystonemiddleware.auth_token \
+         --namespace cotyledon
 
 [testenv:genpolicy]
 basepython = python3