diff --git a/nova/api/openstack/compute/schemas/aggregates.py b/nova/api/openstack/compute/schemas/aggregates.py
index 52f0a6878..5283429e7 100644
--- a/nova/api/openstack/compute/schemas/aggregates.py
+++ b/nova/api/openstack/compute/schemas/aggregates.py
@@ -16,11 +16,11 @@ import copy
 
 from nova.api.validation import parameter_types
 
-availability_zone = copy.deepcopy(parameter_types.name)
-availability_zone['type'] = ['string', 'null']
-availability_zone_with_leading_trailing_spaces = copy.deepcopy(parameter_types.
-    name_with_leading_trailing_spaces)
-availability_zone_with_leading_trailing_spaces['type'] = ['string', 'null']
+availability_zone = {'oneOf': [parameter_types.name, {'type': 'null'}]}
+availability_zone_with_leading_trailing_spaces = {
+    'oneOf': [parameter_types.name_with_leading_trailing_spaces,
+              {'type': 'null'}]
+}
 
 
 create = {
diff --git a/nova/tests/unit/api/openstack/compute/test_aggregates.py b/nova/tests/unit/api/openstack/compute/test_aggregates.py
index f0a738777..76ce73d98 100644
--- a/nova/tests/unit/api/openstack/compute/test_aggregates.py
+++ b/nova/tests/unit/api/openstack/compute/test_aggregates.py
@@ -16,6 +16,7 @@
 """Tests for the aggregates admin api."""
 
 import mock
+import uuid
 from webob import exc
 
 from nova.api.openstack.compute import aggregates as aggregates_v21
@@ -264,6 +265,19 @@ class AggregateTestCaseV21(test.NoDBTestCase):
                                      {"name": "test",
                                       "availability_zone": ""}})
 
+    @mock.patch('nova.compute.api.AggregateAPI.create_aggregate')
+    def test_create_with_none_availability_zone(self, mock_create_agg):
+        mock_create_agg.return_value = objects.Aggregate(self.context,
+                                                         name='test',
+                                                         uuid=uuid.uuid4(),
+                                                         hosts=[],
+                                                         metadata={})
+        body = {"aggregate": {"name": "test",
+                              "availability_zone": None}}
+        result = self.controller.create(self.req, body=body)
+        mock_create_agg.assert_called_once_with(self.context, 'test', None)
+        self.assertEqual(result['aggregate']['name'], 'test')
+
     def test_create_with_extra_invalid_arg(self):
         self.assertRaises(self.bad_request, self.controller.create,
                           self.req, body={"name": "test",
@@ -381,6 +395,21 @@ class AggregateTestCaseV21(test.NoDBTestCase):
         self.assertRaises(self.bad_request, self.controller.update,
                           self.req, "2", body=test_metadata)
 
+    @mock.patch('nova.compute.api.AggregateAPI.update_aggregate')
+    def test_update_with_none_availability_zone(self, mock_update_agg):
+        agg_id = uuid.uuid4()
+        mock_update_agg.return_value = objects.Aggregate(self.context,
+                                                         name='test',
+                                                         uuid=agg_id,
+                                                         hosts=[],
+                                                         metadata={})
+        body = {"aggregate": {"name": "test",
+                              "availability_zone": None}}
+        result = self.controller.update(self.req, agg_id, body=body)
+        mock_update_agg.assert_called_once_with(self.context, agg_id,
+                                                body['aggregate'])
+        self.assertEqual(result['aggregate']['name'], 'test')
+
     def test_update_with_bad_aggregate(self):
         test_metadata = {"aggregate": {"name": "test_name"}}