Allow migrating server with port resource request

Now that the nova code supports such a migration 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 migration 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

Change-Id: I4bda569cc7c247e83219276282724c77e760ddcd
blueprint: support-move-ops-with-qos-ports

Author: Balazs Gibizer

api-guide/source/port_with_resource_request.rst

@@ -18,9 +18,14 @@ However the following API operations are still not supported in nova:
 * Attaching Neutron ports and networks having QoS minimum bandwidth rule is not
   supported.
 
+Also the following API operations are not supported in the 19.0.0 (Stein)
+version of nova:
+
 * Moving (resizing, migrating, live-migrating, evacuating, unshelving after
   shelve offload) servers with ports having resource request is not yet
   supported.
 
-See :nova-doc:`the admin guide <admin/port_with_resource_request.html>` for
-administrative details.
+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.

nova/api/openstack/compute/migrate_server.py

@@ -58,18 +58,8 @@ def _migrate(self, req, id, body):
         instance = common.get_instance(self.compute_api, context, id,
                                        expected_attrs=['flavor'])
 
-        # 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.uuid, self.network_api):
-            if not common.supports_port_resource_request_during_move(req):
-                msg = _("The migrate 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/tests/functional/test_servers.py

@@ -5820,26 +5820,6 @@ def test_resize_server_with_port_resource_request_old_microversion(self):
             'The resize action on a server with ports having resource '
             'requests', six.text_type(ex))
 
-    def test_migrate_server_with_port_resource_request_old_microversion(self):
-        server = self._create_server(
-            flavor=self.flavor,
-            networks=[{'port': self.neutron.port_1['id']}])
-        self._wait_for_state_change(self.admin_api, server, 'ACTIVE')
-
-        # We need to simulate that the above server has a port that has
-        # resource request; we cannot boot with such a port but legacy servers
-        # can exist with such a port.
-        self._add_resource_request_to_a_bound_port(self.neutron.port_1['id'])
-
-        ex = self.assertRaises(
-            client.OpenStackApiException,
-            self.api.post_server_action, server['id'], {'migrate': None})
-
-        self.assertEqual(400, ex.response.status_code)
-        self.assertIn(
-            'The migrate action on a server with ports having resource '
-            'requests', six.text_type(ex))
-
     def test_live_migrate_server_with_port_resource_request_old_microversion(
             self):
         server = self._create_server(
@@ -6362,18 +6342,6 @@ def setUp(self):
         self.flags(weight_classes=[__name__ + '.HostNameWeigher'],
                    group='filter_scheduler')
         super(ServerMoveWithPortResourceRequestTest, self).setUp()
-
-        # The API actively rejecting the move operations with resource
-        # request so we have to turn off that check.
-        # TODO(gibi): Remove this when the move operations are supported and
-        # the API check is removed.
-        patcher = mock.patch(
-            'nova.api.openstack.common.'
-            'supports_port_resource_request_during_move',
-            return_value=True)
-        self.addCleanup(patcher.stop)
-        patcher.start()
-
         self.compute2 = self._start_compute('host2')
         self.compute2_rp_uuid = self._get_provider_uuid_by_host('host2')
         self._create_networking_rp_tree('host2', self.compute2_rp_uuid)

releasenotes/notes/support-cold-migrating-neutron-ports-with-resource-request-6d23be654a253625.yaml

@@ -0,0 +1,9 @@
+---
+features:
+  - |
+    Cold migration is now supported for servers with neutron ports having
+    resource requests. E.g. ports that have QoS minimum bandwidth rules
+    attached. Note that the migration is only supported if both the source and
+    the destination compute services are upgraded to Train and the
+    ``[upgrade_levels]/compute`` configuration does not prevent the computes
+    from using the latest RPC version.