Set 'old_flavor', 'new_flavor' on source before resize

Cross-cell resize is confusing. We need to set this information ahead of
time.

Change-Id: I5a403c072b9f03074882b552e1925f22cb5b15b6
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>
Partial-Bug: #1879878

nova/conductor/tasks/cross_cell_migrate.py

@@ -392,18 +392,23 @@ class PrepResizeAtSourceTask(base.TaskBase):
     ``resize_migrated`` and the migration.status will be ``post-migrating``.
     """
 
-    def __init__(self, context, instance, migration, request_spec,
-                 compute_rpcapi, image_api):
+    def __init__(
+        self, context, instance, flavor, migration, request_spec,
+        compute_rpcapi, image_api,
+    ):
         """Initializes this PrepResizeAtSourceTask instance.
 
         :param context: nova auth context targeted at the source cell
         :param instance: Instance object from the source cell
+        :param flavor: The new flavor if performing resize and not just a
+            cold migration
         :param migration: Migration object from the source cell
         :param request_spec: RequestSpec object for the resize operation
         :param compute_rpcapi: instance of nova.compute.rpcapi.ComputeAPI
         :param image_api: instance of nova.image.glance.API
         """
         super(PrepResizeAtSourceTask, self).__init__(context, instance)
+        self.flavor = flavor
         self.migration = migration
         self.request_spec = request_spec
         self.compute_rpcapi = compute_rpcapi
@@ -416,6 +421,8 @@ class PrepResizeAtSourceTask(base.TaskBase):
         # guest should be powered on.
         self.instance.system_metadata['old_vm_state'] = self.instance.vm_state
         self.instance.task_state = task_states.RESIZE_MIGRATING
+        self.instance.old_flavor = self.instance.flavor
+        self.instance.new_flavor = self.flavor
 
         # If the instance is not volume-backed, create a snapshot of the root
         # disk.
@@ -782,7 +789,7 @@ class CrossCellMigrationTask(base.TaskBase):
         LOG.debug('Preparing source host %s for cross-cell resize.',
                   self.source_migration.source_compute, instance=self.instance)
         prep_source_task = PrepResizeAtSourceTask(
-            self.context, self.instance, self.source_migration,
+            self.context, self.instance, self.flavor, self.source_migration,
             self.request_spec, self.compute_rpcapi, self.image_api)
         snapshot_id = prep_source_task.execute()
         self._completed_tasks['PrepResizeAtSourceTask'] = prep_source_task
@@ -960,9 +967,6 @@ class ConfirmResizeTask(base.TaskBase):
             ctxt, self.migration.uuid)
         LOG.debug('Cleaning up source host %s for cross-cell resize confirm.',
                   source_migration.source_compute, instance=source_instance)
-        # The instance.old_flavor field needs to be set before the source
-        # host drops the MoveClaim in the ResourceTracker.
-        source_instance.old_flavor = source_instance.flavor
         # Use the EventReport context manager to create the same event that
         # the source compute will create but in the target cell DB so we do not
         # have to explicitly copy it over from source to target DB.
@@ -1303,7 +1307,6 @@ class RevertResizeTask(base.TaskBase):
         # source cell instance for doing the revert on the source compute host.
         instance.system_metadata['old_vm_state'] = (
             self.instance.system_metadata.get('old_vm_state'))
-        instance.old_flavor = instance.flavor
         instance.task_state = task_states.RESIZE_REVERTING
         instance.save()
 

nova/tests/functional/regressions/test_bug_1879878.py

@@ -270,8 +270,7 @@ class TestCrossCell(integrated_helpers.ProviderUsageBaseTestCase):
 
         def fake_cleanup(_self, _context, _instance, *args, **kwargs):
             self.assertIsNotNone(_instance.old_flavor)
-            # FIXME(stephenfin): This should not be unset
-            self.assertIsNone(_instance.new_flavor)
+            self.assertIsNotNone(_instance.new_flavor)
             return orig_cleanup(_self, _context, _instance, *args, **kwargs)
 
         # TODO(stephenfin): Use a helper
@@ -331,8 +330,7 @@ class TestCrossCell(integrated_helpers.ProviderUsageBaseTestCase):
 
         def fake_finish_revert_migration(_self, _context, _instance, *a, **kw):
             self.assertIsNotNone(_instance.old_flavor)
-            # FIXME(stephenfin): This should not be unset
-            self.assertIsNone(_instance.new_flavor)
+            self.assertIsNotNone(_instance.new_flavor)
             return orig_finish_revert(_self, _context, _instance, *a, **kw)
 
         # TODO(stephenfin): Use a helper

nova/tests/unit/conductor/tasks/test_cross_cell_migrate.py

@@ -804,7 +804,10 @@ class PrepResizeAtSourceTaskTestCase(test.NoDBTestCase):
                 vm_state=vm_states.ACTIVE,
                 display_name='fake-server',
                 system_metadata={},
-                host='source.host.com'),
+                host='source.host.com',
+                flavor=objects.Flavor(),
+            ),
+            objects.Flavor(),
             objects.Migration(),
             objects.RequestSpec(),
             compute_rpcapi=mock.Mock(),
@@ -828,6 +831,8 @@ class PrepResizeAtSourceTaskTestCase(test.NoDBTestCase):
         # The instance should have been updated.
         instance_save.assert_called_once_with(
             expected_task_state=task_states.RESIZE_PREP)
+        self.assertIs(self.task.instance.old_flavor, self.task.instance.flavor)
+        self.assertIs(self.task.instance.new_flavor, self.task.flavor)
         self.assertEqual(
             task_states.RESIZE_MIGRATING, self.task.instance.task_state)
         self.assertEqual(self.task.instance.vm_state,
@@ -855,6 +860,8 @@ class PrepResizeAtSourceTaskTestCase(test.NoDBTestCase):
         # The instance should have been updated.
         instance_save.assert_called_once_with(
             expected_task_state=task_states.RESIZE_PREP)
+        self.assertIs(self.task.instance.old_flavor, self.task.instance.flavor)
+        self.assertIs(self.task.instance.new_flavor, self.task.flavor)
         self.assertEqual(
             task_states.RESIZE_MIGRATING, self.task.instance.task_state)
         self.assertEqual(self.task.instance.vm_state,
@@ -1182,7 +1189,6 @@ class ConfirmResizeTaskTestCase(test.NoDBTestCase):
                                     uuid=uuids.instance,
                                     flavor=objects.Flavor())
         self.task._cleanup_source_host(instance)
-        self.assertIs(instance.old_flavor, instance.flavor)
         mock_action_start.assert_called_once_with(
             instance._context, instance.uuid, instance_actions.CONFIRM_RESIZE,
             want_result=False)
@@ -1434,8 +1440,6 @@ class RevertResizeTaskTestCase(test.NoDBTestCase, ObjectComparatorMixin):
         # Fields on the source cell instance should have been updated.
         self.assertEqual(vm_states.ACTIVE,
                          source_cell_instance.system_metadata['old_vm_state'])
-        self.assertIs(source_cell_instance.old_flavor,
-                      source_cell_instance.flavor)
         self.assertEqual(task_states.RESIZE_REVERTING,
                          source_cell_instance.task_state)
         mock_inst_save.assert_called_once_with()