Remove "live_migration_events" configuration option

This option was introduced in [1]. This option depended on [2],
the Nova code enabling this feature, that filters the
"vif-plugged-event" to be sent to Nova.

Now the default behaviour is "True".

Related-Bug: #1901707

[1]https://review.opendev.org/c/openstack/neutron/+/766277
[2]https://review.opendev.org/c/openstack/nova/+/767368

Change-Id: I05f7e6a7d91f6a4a1fe6d4765589f30257243628

neutron/agent/rpc.py

@@ -342,9 +342,8 @@ class CacheBackedPluginApi(PluginApi):
             port_obj.bindings, constants.ACTIVE, raise_if_not_found=True,
             port_id=port_obj.id)
         migrating_to = migrating_to_host(port_obj.bindings)
-        if (not (migrating_to and cfg.CONF.nova.live_migration_events) and
-                port_obj.device_owner.startswith(
-                    constants.DEVICE_OWNER_COMPUTE_PREFIX) and
+        if (not migrating_to and port_obj.device_owner.startswith(
+                constants.DEVICE_OWNER_COMPUTE_PREFIX) and
                 binding[pb_ext.HOST] != host):
             LOG.debug("Device %s has no active binding in this host",
                       port_obj)

neutron/conf/common.py

@@ -179,24 +179,6 @@ nova_opts = [
                help=_('Type of the nova endpoint to use.  This endpoint will'
                       ' be looked up in the keystone catalog and should be'
                       ' one of public, internal or admin.')),
-    cfg.BoolOpt('live_migration_events', default=False,
-                help=_('When this option is enabled, during the live '
-                       'migration, the OVS agent will only send the '
-                       '"vif-plugged-event" when the destination host '
-                       'interface is bound. This option also disables any '
-                       'other agent (like DHCP) to send to Nova this event '
-                       'when the port is provisioned.'
-                       'This option can be enabled if Nova patch '
-                       'https://review.opendev.org/c/openstack/nova/+/767368 '
-                       'is in place.'
-                       'This option is temporary and will be removed in Y and '
-                       'the behavior will be "True".'),
-                deprecated_for_removal=True,
-                deprecated_reason=(
-                    'In Y the Nova patch '
-                    'https://review.opendev.org/c/openstack/nova/+/767368 '
-                    'will be in the code even when running a Nova server in '
-                    'X.')),
 ]
 
 

neutron/plugins/ml2/plugin.py

@@ -369,8 +369,7 @@ class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
 
         host_migrating = agent_rpc.migrating_to_host(
             getattr(port, 'port_bindings', []))
-        if (host_migrating and cfg.CONF.nova.live_migration_events and
-                self.nova_notifier):
+        if host_migrating and self.nova_notifier:
             send_nova_event = bool(trigger ==
                                    provisioning_blocks.L2_AGENT_ENTITY)
             with self.nova_notifier.context_enabled(send_nova_event):

neutron/tests/unit/agent/test_rpc.py

@@ -352,21 +352,13 @@ class TestCacheBackedPluginApi(base.BaseTestCase):
         self.assertIn(constants.NO_ACTIVE_BINDING, entry)
 
     def test_get_device_details_migrating_to_host(self):
-        for live_migration_events, migrating_to in ((True, 'host2'),
-                                                    (False, 'irrelevant')):
-            cfg.CONF.set_override('live_migration_events',
-                                  live_migration_events, group='nova')
-            profile = jsonutils.dumps({'migrating_to': migrating_to})
-            self._port.bindings[0].profile = profile
-            self._api.remote_resource_cache.get_resource_by_id.side_effect = [
-                self._port, self._network]
-            entry = self._api.get_device_details(mock.ANY, self._port_id,
-                                                 mock.ANY, 'host2')
-            if live_migration_events:
-                self.assertEqual('host2', entry['migrating_to'])
-            else:
-                self.assertTrue(entry[constants.NO_ACTIVE_BINDING])
-                self.assertNotIn('migrating_to', entry)
+        profile = jsonutils.dumps({'migrating_to': 'host2'})
+        self._port.bindings[0].profile = profile
+        self._api.remote_resource_cache.get_resource_by_id.side_effect = [
+            self._port, self._network]
+        entry = self._api.get_device_details(mock.ANY, self._port_id,
+                                             mock.ANY, 'host2')
+        self.assertEqual('host2', entry['migrating_to'])
 
     @mock.patch('neutron.agent.resource_cache.RemoteResourceCache')
     def test_initialization_with_default_resources(self, rcache_class):

releasenotes/notes/remove-live_migration_events-f9dd9eacfdf32f97.yaml

@@ -0,0 +1,7 @@
+---
+upgrade:
+  - |
+    The ``live_migration_events`` configuration option is removed. Now Neutron
+    assumes this flag is always set. This configuration option depended on
+    the Nova patch
+    `only wait for plugtime events in pre-live-migration <https://review.opendev.org/c/openstack/nova/+/767368>`_.

zuul.d/tempest-multinode.yaml

@@ -205,9 +205,6 @@
         s-proxy: false
       devstack_local_conf:
         post-config:
-          $NEUTRON_CONF:
-            nova:
-              live_migration_events: True
           $NEUTRON_L3_CONF:
             agent:
               debug_iptables_rules: True
@@ -239,9 +236,6 @@
           c-vol: false
         devstack_local_conf:
           post-config:
-            $NEUTRON_CONF:
-              nova:
-                live_migration_events: True
             $NEUTRON_L3_CONF:
               agent:
                 debug_iptables_rules: True