Adds a repoducer for post live migration fail

Adds a regression test or repoducer for post live migration
fail at destination, the possible casue can be fail to get
instance network info or  block device info

changes:
adds return server from _live_migrate in _integrated_helpers

NOTE(auniyal): Differences
  * Replaced GlanceFixture with fake.stub_out_image_service in regression test, as GlanceFixture does not exist in Ussuri

Related-Bug: #1628606
Change-Id: I48dbe0aae8a3943fdde69cda1bd663d70ea0eb19
(cherry picked from commit a20baeca1f5ebb0dfe9607335a6986e9ed0e1725)
(cherry picked from commit 74a618a8118642c9fd32c4e0d502d12ac826affe)
(cherry picked from commit 71e5a1dbcc22aeaa798d3d06ce392cf73364b8db)
(cherry picked from commit 5efcc3f695e02d61cb8b881e009308c2fef3aa58)
(cherry picked from commit ed1ea71489b60c0f95d76ab05f554cd046c60bac)
(cherry picked from commit 6dda4f7ca3f25a11cd0178352ad24fe2e8b74785)

2 files changed, 65 insertions, 3 deletions

diff --git a/nova/tests/functional/integrated_helpers.py b/nova/tests/functional/integrated_helpers.py
index 53d10d2353..07d1f7b826 100644
--- a/nova/tests/functional/integrated_helpers.py
+++ b/nova/tests/functional/integrated_helpers.py
@@ -436,10 +436,10 @@ class InstanceHelperMixin:
                       server_expected_state='ACTIVE'):
         self.api.post_server_action(
             server['id'],
-            {'os-migrateLive': {'host': None,
-                                'block_migration': 'auto'}})
-        self._wait_for_state_change(server, server_expected_state)
+            {'os-migrateLive': {'host': None, 'block_migration': 'auto'}})
+        server = self._wait_for_state_change(server, server_expected_state)
         self._wait_for_migration_status(server, [migration_expected_state])
+        return server
 
     def _evacuate_server(
             self, server, extra_post_args=None, expected_host=None,
diff --git a/nova/tests/functional/regressions/test_bug_1628606.py b/nova/tests/functional/regressions/test_bug_1628606.py
new file mode 100644
index 0000000000..22bb219c1b
--- /dev/null
+++ b/nova/tests/functional/regressions/test_bug_1628606.py
@@ -0,0 +1,62 @@
+# 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.
+
+from nova import test
+from nova.tests import fixtures as nova_fixtures
+from nova.tests.functional.api import client
+from nova.tests.functional import fixtures as func_fixtures
+from nova.tests.functional import integrated_helpers
+from nova.tests.unit.image import fake
+from unittest import mock
+
+
+class PostLiveMigrationFail(
+    test.TestCase, integrated_helpers.InstanceHelperMixin):
+    """Regression test for bug 1628606
+    """
+
+    def setUp(self):
+        super().setUp()
+        self.useFixture(nova_fixtures.NeutronFixture(self))
+        fake.stub_out_image_service(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')
+
+    @mock.patch(
+        'nova.compute.manager.ComputeManager'
+        '._post_live_migration_remove_source_vol_connections')
+    def test_post_live_migration(self, mock_migration):
+        server = self._create_server(networks=[])
+        self.assertEqual(self.src.host, server['OS-EXT-SRV-ATTR:host'])
+
+        error = client.OpenStackApiException(
+            "Failed to remove source vol connection post live migration")
+        mock_migration.side_effect = error
+
+        server = self._live_migrate(
+            server, migration_expected_state='error',
+            server_expected_state='ERROR')
+        # FIXME(amit): this should point to the dest as after migration
+        # but does not because of bug 1628606
+        self.assertEqual(self.src.host, server['OS-EXT-SRV-ATTR:host'])