Use admin neutron client to gather port resource requests

The network_api get_requested_resource_for_instance() creates a neutron
client with the current request context and uses the client to query
neutron ports. Neutron does not return the resource_request of the
neutron port if it is queried by a non-admin. So if the request context
was a non admin context nova thought that none of the ports have resource
requests.

This patch ensures that an admin client is used to query the ports.

Change-Id: I1178fb77a74010c3b9f51eea22c7e7576b600015
Closes-Bug: #1849695
(cherry picked from commit 38a214466f)

nova/network/neutronv2/api.py

@@ -2231,7 +2231,11 @@ class API(base_api.NetworkAPI):
         :return: A list of RequestGroup objects
         """
 
-        neutron = get_client(context)
+        # NOTE(gibi): We need to use an admin client as otherwise a non admin
+        # initiated resize causes that neutron does not fill the
+        # resource_request field of the port and this will lead to resource
+        # allocation issues. See bug 1849695
+        neutron = get_client(context, admin=True)
         # get the ports associated to this instance
         data = neutron.list_ports(
             device_id=instance_uuid, fields=['id', 'resource_request'])

nova/tests/unit/network/test_neutronv2.py

@@ -6151,6 +6151,8 @@ class TestNeutronv2WithMock(TestNeutronv2Base):
             uuids.port1,
             request_groups[0].requester_id)
 
+        mock_get_client.assert_called_once_with(self.context, admin=True)
+
 
 class TestNeutronv2ModuleMethods(test.NoDBTestCase):