Fix image-defined numa claims during evacuate

When evacuating, the API does not send the image_ref
to the compute so currently the compute manager
rebuild_instance() method will just pass an empty
dict for image_meta to the rebuild_claim, which means
if the server was originally created with an image that
has numa-related constraints, like hw_numa_nodes, those
constraints would not be applied to the destination host
during the evacuate.

This change simply checks for evacuate if image_ref is
not provided and pulls the image_meta off the instance
which was stashed in the instance.system_metadata during
server create (see get_system_metadata_from_image usage
in the compute API).

This fix was ported from the starlingx-staging/stx-nova
repo commit 71acfeae0.

Change-Id: If548fa3436174b1eae08cdcf6578020cc0c7b81f
Closes-Bug: #1785318

nova/compute/manager.py

@@ -2984,6 +2984,12 @@ class ComputeManager(manager.Manager):
         image_meta = {}
         if image_ref:
             image_meta = self.image_api.get(context, image_ref)
+        elif evacuate:
+            # For evacuate the API does not send down the image_ref since the
+            # image does not change so just get it from what was stashed in
+            # the instance system_metadata when the instance was created (or
+            # last rebuilt). This also works for volume-backed instances.
+            image_meta = instance.image_meta
 
         # NOTE(mriedem): On an evacuate, we need to update
         # the instance's host and node properties to reflect it's

nova/tests/unit/compute/test_compute.py

@@ -12661,6 +12661,7 @@ class EvacuateHostTestCase(BaseTestCase):
         super(EvacuateHostTestCase, self).setUp()
         self.inst = self._create_fake_instance_obj(
             {'host': 'fake_host_2', 'node': 'fakenode2'})
+        self.inst.system_metadata = {}
         self.inst.task_state = task_states.REBUILDING
         self.inst.save()
 
@@ -12941,10 +12942,8 @@ class EvacuateHostTestCase(BaseTestCase):
             block_device_info=mock.ANY)
 
     @mock.patch.object(fake.FakeDriver, 'spawn')
-    @mock.patch('nova.objects.Instance.image_meta',
-                new_callable=mock.PropertyMock)
     def test_on_shared_storage_not_provided_host_with_shared_storage(self,
-            mock_image_meta, mock_spawn):
+            mock_spawn):
         self.stub_out('nova.virt.fake.FakeDriver.instance_on_disk',
                       lambda *a, **ka: True)
 
@@ -12953,7 +12952,7 @@ class EvacuateHostTestCase(BaseTestCase):
         mock_spawn.assert_called_once_with(
             test.MatchType(context.RequestContext),
             test.MatchType(objects.Instance),
-            mock_image_meta.return_value,
+            test.MatchType(objects.ImageMeta),
             mock.ANY, 'newpass', mock.ANY,
             network_info=mock.ANY,
             block_device_info=mock.ANY)

nova/tests/unit/compute/test_compute_mgr.py

@@ -4150,6 +4150,7 @@ class ComputeManagerUnitTestCase(test.NoDBTestCase):
                                            mock_elevated):
         mock_elevated.return_value = self.context
         instance = fake_instance.fake_instance_obj(self.context)
+        instance.system_metadata = {}
         ex = test.TestingException('foo')
         with mock.patch.object(self.compute, '_get_resource_tracker') as mrt:
             self.assertRaises(test.TestingException,
@@ -4223,6 +4224,7 @@ class ComputeManagerUnitTestCase(test.NoDBTestCase):
             mock_instance_fault):
         instance = fake_instance.fake_instance_obj(self.context)
         instance.info_cache = None
+        instance.system_metadata = {}
         elevated_context = mock.Mock()
         mock_context_elevated.return_value = elevated_context
         request_spec = objects.RequestSpec()
@@ -4266,8 +4268,10 @@ class ComputeManagerUnitTestCase(test.NoDBTestCase):
 
     def test_rebuild_node_updated_if_recreate(self):
         dead_node = uuidutils.generate_uuid()
+        img_sys_meta = {'image_hw_numa_nodes': 1}
         instance = fake_instance.fake_instance_obj(self.context,
                                                    node=dead_node)
+        instance.system_metadata = img_sys_meta
         instance.migration_context = None
         with test.nested(
             mock.patch.object(self.compute, '_get_resource_tracker'),
@@ -4284,6 +4288,15 @@ class ComputeManagerUnitTestCase(test.NoDBTestCase):
             self.assertEqual('new-node', instance.node)
             mock_set.assert_called_once_with(None, 'done')
             mock_rt.assert_called_once_with()
+            # Make sure the rebuild_claim was called with the proper image_meta
+            # from the instance.
+            mock_rebuild_claim = mock_rt.return_value.rebuild_claim
+            mock_rebuild_claim.assert_called_once()
+            self.assertIn('image_meta', mock_rebuild_claim.call_args[1])
+            actual_image_meta = mock_rebuild_claim.call_args[1][
+                'image_meta'].properties
+            self.assertIn('hw_numa_nodes', actual_image_meta)
+            self.assertEqual(1, actual_image_meta.hw_numa_nodes)
 
     @mock.patch.object(compute_utils, 'notify_about_instance_rebuild')
     @mock.patch.object(compute_utils, 'notify_usage_exists')