Allow resizing server with port resource request

This patch adds functional coverage for such resize. No extra code
changes were needed on top of the migrate patches to make resize work.

Now that the nova code supports the resize this patch removes the
check from the API that rejected the operation.

Note that in the spec [1] we agreed not to introduce new microversion
for this change but treat it as a bugfix. The current change also makes
it possible to accept the resize of these servers with _any_
microversion.

[1] https://specs.openstack.org/openstack/nova-specs/specs/train/approved/support-move-ops-with-qos-ports.html#rest-api-impact

blueprint: support-move-ops-with-qos-ports

Change-Id: Id0ee10e8d323786f4d79c82e3f05b48e76bd0956

Author: Balazs Gibizer

api-guide/source/port_with_resource_request.rst

@@ -25,7 +25,11 @@ version of nova:
   shelve offload) servers with ports having resource request is not yet
   supported.
 
-As of 20.0.0 (Train), nova supports cold migrating servers with neutron ports
-having resource requests if both the source and destination compute services
-are upgraded to 20.0.0 (Train) and the ``[upgrade_levels]/compute``
-configuration does not prevent the computes from using the latest RPC version.
+As of 20.0.0 (Train), nova supports cold migrating and resizing servers with
+neutron ports having resource requests if both the source and destination
+compute services are upgraded to 20.0.0 (Train) and the
+``[upgrade_levels]/compute`` configuration does not prevent the computes from
+using the latest RPC version.
+
+See :nova-doc:`the admin guide <admin/port_with_resource_request.html>` for
+administrative details.

nova/api/openstack/compute/servers.py

@@ -940,18 +940,8 @@ def _resize(self, req, instance_id, flavor_id, **kwargs):
                     target={'user_id': instance.user_id,
                             'project_id': instance.project_id})
 
-        # We could potentially move this check to conductor and avoid the
-        # extra API call to neutron when we support move operations with ports
-        # having resource requests.
         if common.instance_has_port_with_resource_request(
                 context, instance_id, self.network_api):
-            if not common.supports_port_resource_request_during_move(req):
-                msg = _("The resize action on a server with ports having "
-                        "resource requests, like a port with a QoS minimum "
-                        "bandwidth policy, is not supported with this "
-                        "microversion")
-                raise exc.HTTPBadRequest(explanation=msg)
-
             # TODO(gibi): Remove when nova only supports compute newer than
             # Train
             source_service = objects.Service.get_by_host_and_binary(

nova/compute/manager.py

@@ -4284,7 +4284,8 @@ def finish_revert_resize(
             instance.save()
 
             try:
-                self._revert_allocation(context, instance, migration)
+                source_allocations = self._revert_allocation(
+                    context, instance, migration)
             except exception.AllocationMoveFailed:
                 LOG.error('Reverting allocation in placement for migration '
                           '%(migration_uuid)s failed. The instance '
@@ -4295,16 +4296,12 @@ def finish_revert_resize(
                 raise
 
             if request_spec:
-                # TODO(gibi): the _revert_allocation() call above already
-                # fetched the original allocation of the instance so we could
-                # avoid this second call to placement
                 # NOTE(gibi): We need to re-calculate the resource provider -
                 # port mapping as we have to have the neutron ports allocate
                 # from the source compute after revert.
-                allocs = self.reportclient.get_allocations_for_consumer(
-                    context, instance.uuid)
                 scheduler_utils.fill_provider_mapping_based_on_allocation(
-                    context, self.reportclient, request_spec, allocs)
+                    context, self.reportclient, request_spec,
+                    source_allocations)
                 provider_mappings = self._get_request_group_mapping(
                     request_spec)
             else:
@@ -4391,7 +4388,7 @@ def _revert_allocation(self, context, instance, migration):
         # TODO(cdent): Should we be doing anything with return values here?
         self.reportclient.move_allocations(context, migration.uuid,
                                            instance.uuid)
-        return True
+        return orig_alloc
 
     def _prep_resize(self, context, image, instance, instance_type,
                      filter_properties, node, migration, request_spec,

nova/tests/functional/integrated_helpers.py

@@ -433,10 +433,10 @@ def setUp(self):
 
         placement = self.useFixture(func_fixtures.PlacementFixture())
         self.placement_api = placement.api
-        api_fixture = self.useFixture(nova_fixtures.OSAPIFixture(
+        self.api_fixture = self.useFixture(nova_fixtures.OSAPIFixture(
             api_version='v2.1'))
 
-        self.admin_api = api_fixture.admin_api
+        self.admin_api = self.api_fixture.admin_api
         self.admin_api.microversion = self.microversion
         self.api = self.admin_api