Merge "Drop source node allocations if finish_resize fails"

Author: Zuul

nova/compute/manager.py

@@ -4776,7 +4776,22 @@ def finish_resize(self, context, disk_info, image, instance,
                                        migration)
         except Exception:
             with excutils.save_and_reraise_exception():
-                self._revert_allocation(context, instance, migration)
+                # At this point, resize_instance (which runs on the source) has
+                # already updated the instance host/node values to point to
+                # this (the dest) compute, so we need to leave the allocations
+                # against the dest node resource provider intact and drop the
+                # allocations against the source node resource provider. If the
+                # user tries to recover the server by hard rebooting it, it
+                # will happen on this host so that's where the allocations
+                # should go. Note that this is the same method called from
+                # confirm_resize to cleanup the source node allocations held
+                # by the migration record.
+                LOG.info('Deleting allocations for old flavor on source node '
+                         '%s after finish_resize failure. You may be able to '
+                         'recover the instance by hard rebooting it.',
+                         migration.source_compute, instance=instance)
+                self._delete_allocation_after_move(
+                    context, instance, migration)
 
     def _finish_resize_helper(self, context, disk_info, image, instance,
                               migration):

nova/tests/functional/regressions/test_bug_1825537.py

@@ -66,16 +66,9 @@ def test_finish_resize_fails_allocation_cleanup(self):
         # allocations should still exist with the new flavor.
         source_rp_uuid = self._get_provider_uuid_by_host('host1')
         dest_rp_uuid = self._get_provider_uuid_by_host('host2')
-        # FIXME(mriedem): This is bug 1825537 where the allocations are
-        # reverted when finish_resize fails so the dest node resource provider
-        # does not have any allocations and the instance allocations are for
-        # the old flavor on the source node resource provider even though the
-        # instance is not running on the source host nor pointed at the source
-        # host in the DB.
-        # self.assertFlavorMatchesAllocation(
-        #     self.flavor2, server['id'], dest_rp_uuid)
-        dest_rp_usages = self._get_provider_usages(dest_rp_uuid)
-        no_usage = {'VCPU': 0, 'MEMORY_MB': 0, 'DISK_GB': 0}
-        self.assertEqual(no_usage, dest_rp_usages)
         self.assertFlavorMatchesAllocation(
-            self.flavor1, server['id'], source_rp_uuid)
+            self.flavor2, server['id'], dest_rp_uuid)
+        # And the source node provider should not have any usage.
+        source_rp_usages = self._get_provider_usages(source_rp_uuid)
+        no_usage = {'VCPU': 0, 'MEMORY_MB': 0, 'DISK_GB': 0}
+        self.assertEqual(no_usage, source_rp_usages)

nova/tests/functional/test_servers.py

@@ -3092,10 +3092,13 @@ def fake_resize_method(*args, **kwargs):
 
         # Ensure the allocation records still exist on the host.
         source_rp_uuid = self._get_provider_uuid_by_host(hostname)
-        # FIXME(mriedem): This is wrong for the _finish_resize case.
-        # The new_flavor should have been subtracted from the doubled
-        # allocation which just leaves us with the original flavor.
-        self.assertFlavorMatchesUsage(source_rp_uuid, self.flavor1)
+        if failing_method == '_finish_resize':
+            # finish_resize will drop the old flavor allocations.
+            self.assertFlavorMatchesUsage(source_rp_uuid, self.flavor2)
+        else:
+            # The new_flavor should have been subtracted from the doubled
+            # allocation which just leaves us with the original flavor.
+            self.assertFlavorMatchesUsage(source_rp_uuid, self.flavor1)
 
     def test_resize_to_same_host_prep_resize_fails(self):
         self._test_resize_to_same_host_instance_fails(