Adds a repoducer for post_live_migration_at_destination failures

Adds a reproducer for post_live_migration_at_destination
failure due to keystone or neutron service being unavailable.

Related-Bug: #2000069
Change-Id: I4f877940c0e830cd7ec19476289d70ff10443c75

Author: uggla

nova/tests/functional/regressions/test_bug_2143972.py

@@ -0,0 +1,89 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import nova
+
+from nova import test
+from nova.tests import fixtures as nova_fixtures
+from nova.tests.functional import fixtures as func_fixtures
+from nova.tests.functional import integrated_helpers
+import oslo_messaging as messaging
+from unittest import mock
+
+
+class PostLiveMigrationFail(
+    test.TestCase, integrated_helpers.InstanceHelperMixin):
+    """Regression test for bug 2143972
+    """
+
+    def setUp(self):
+        super().setUp()
+        self.useFixture(nova_fixtures.NeutronFixture(self))
+        self.glance = self.useFixture(nova_fixtures.GlanceFixture(self))
+        self.useFixture(func_fixtures.PlacementFixture())
+        self.useFixture(nova_fixtures.HostNameWeigherFixture())
+
+        self.start_service('conductor')
+        self.start_service('scheduler')
+
+        api_fixture = self.useFixture(nova_fixtures.OSAPIFixture(
+            api_version='v2.1'))
+
+        self.api = api_fixture.admin_api
+        self.api.microversion = 'latest'
+
+        self.src = self._start_compute(host='host1')
+        self.dest = self._start_compute(host='host2')
+
+    def test_post_live_migration_keystone_fails(self):
+        """Test for bug 2143972.
+        This test simulate a service failure during post live migration.
+        """
+        orig_function = nova.network.neutron.API.setup_networks_on_host
+        service_exception = messaging.RemoteError(
+            exc_type="Remote Error",
+            value="ServiceUnavailable The server is currently "
+            "unavailable.")
+        self.count_call = 0
+
+        # Fist setup_networks_on_host call is in the pre_live_migration method.
+        # Second setup_networks_on_host call is in the post_live_migration
+        # method.
+        def fake_setup_networks_on_host(*args, **kwargs):
+            """Call the original function first and then raise an exception
+            simulating keystone or neutron not available.
+            """
+            self.count_call += 1
+            if self.count_call > 1:
+                raise service_exception
+            return orig_function(*args, **kwargs)
+
+        server = self._create_server(networks=[])
+        self.assertEqual(self.src.host, server['OS-EXT-SRV-ATTR:host'])
+
+        with mock.patch(
+            'nova.network.neutron.API.setup_networks_on_host',
+            side_effect=fake_setup_networks_on_host
+        ):
+
+            # FIXME(Uggla) A failure with post_live_migration_at_destination
+            # leave the instance in MIGRATING status and
+            # migration_expected_state to completed because the exception
+            # is not raised by the compute manager.  This is mainly due to
+            # the previous behavior that would not want to break, allowing a
+            # migration cleanup.  A recent patch allows better handling of post
+            # migration errors, so we can now raise an exception in such cases.
+            server = self._live_migrate(
+                server, migration_expected_state='completed',
+                server_expected_state='MIGRATING')
+
+            self.assertEqual(self.src.host, server['OS-EXT-SRV-ATTR:host'])