Workaround missing RequestSpec.instance_group.uuid

It's clear that we could have a RequestSpec.instance_group
without a uuid field if the InstanceGroup is set from the
_populate_group_info method which should only be used for
legacy translation of request specs using legacy filter
properties dicts.

To workaround the issue, we look for the group scheduler hint
to get the group uuid before loading it from the DB.

The related functional regression recreate test is updated
to show this solves the issue.

Change-Id: I20981c987549eec40ad9762e74b0db16e54f4e63
Closes-Bug: #1830747
(cherry picked from commit da453c2bfe86ab7a825f0aa7ebced15886f7a5fd)
(cherry picked from commit 8569eb9b4fb905cb92041b84c293dc4e7af27fa8)
(cherry picked from commit 9fed1803b4d6b2778c47add9c327f0610edc5952)
(cherry picked from commit 20b90f2e26e6a46a12c2fd943b4472c3147528fa)
(cherry picked from commit 79cc08642172a3df1cd8d7a7c413adc21b468dcf)

2 files changed, 14 insertions, 15 deletions

diff --git a/nova/objects/request_spec.py b/nova/objects/request_spec.py
index f3529f3cd8..fb3c52948f 100644
--- a/nova/objects/request_spec.py
+++ b/nova/objects/request_spec.py
@@ -197,6 +197,8 @@ class RequestSpec(base.NovaObject):
             policies = list(filter_properties.get('group_policies'))
             hosts = list(filter_properties.get('group_hosts'))
             members = list(filter_properties.get('group_members'))
+            # TODO(mriedem): We could try to get the group uuid from the
+            # group hint in the filter_properties.
             self.instance_group = objects.InstanceGroup(policies=policies,
                                                         hosts=hosts,
                                                         members=members)
@@ -439,6 +441,12 @@ class RequestSpec(base.NovaObject):
         spec._context = context
 
         if 'instance_group' in spec and spec.instance_group:
+            # NOTE(mriedem): We could have a half-baked instance group with no
+            # uuid if some legacy translation was performed on this spec in the
+            # past. In that case, try to workaround the issue by getting the
+            # group uuid from the scheduler hint.
+            if 'uuid' not in spec.instance_group:
+                spec.instance_group.uuid = spec.get_scheduler_hint('group')
             # NOTE(danms): We don't store the full instance group in
             # the reqspec since it would be stale almost immediately.
             # Instead, load it by uuid here so it's up-to-date.
diff --git a/nova/tests/functional/regressions/test_bug_1830747.py b/nova/tests/functional/regressions/test_bug_1830747.py
index 0ceb45f823..ed9b069868 100644
--- a/nova/tests/functional/regressions/test_bug_1830747.py
+++ b/nova/tests/functional/regressions/test_bug_1830747.py
@@ -11,11 +11,9 @@
 # under the License.
 
 import mock
-import six
 
 import nova.conf
 from nova import context as nova_context
-from nova import exception
 from nova import objects
 from nova.scheduler import weights
 from nova import test
@@ -137,17 +135,10 @@ class MissingReqSpecInstanceGroupUUIDTestCase(
         with mock.patch.dict(host1_driver.capabilities,
                              supports_migrate_to_same_host=False):
             self.api.post_server_action(server['id'], {'migrate': None})
-            # FIXME(mriedem): Due to bug 1830747 we don't go to VERIFY_RESIZE
-            # because the reschedule fails and the instance is put into
-            # ERROR status. When the bug is fixed the status should be
-            # VERIFY_RESIZE and the server should be on host2.
             server = self._wait_for_state_change(
-                self.api, server, 'ERROR')
-            self.assertEqual('host1', server['OS-EXT-SRV-ATTR:host'])
-
-        # And the RequestSpec.instance_group.uuid should be missing which
-        # leads to us failing to load the RequestSpec.
-        ex = self.assertRaises(exception.ObjectActionError,
-                               objects.RequestSpec.get_by_instance_uuid,
-                               ctxt, server['id'])
-        self.assertIn('unable to load uuid', six.text_type(ex))
+                self.api, server, 'VERIFY_RESIZE')
+            self.assertEqual('host2', server['OS-EXT-SRV-ATTR:host'])
+
+        # The RequestSpec.instance_group.uuid should still be set.
+        reqspec = objects.RequestSpec.get_by_instance_uuid(ctxt, server['id'])
+        self.assertEqual(group_id, reqspec.instance_group.uuid)