diff --git a/nova/objects/base.py b/nova/objects/base.py
index fef9a44..c4c3f9f 100644
--- a/nova/objects/base.py
+++ b/nova/objects/base.py
@@ -783,11 +783,13 @@ class NovaObjectSerializer(messaging.NoOpSerializer):
             return iterable(**{k: action_fn(context, v)
                             for k, v in six.iteritems(values)})
         else:
-            # NOTE(danms): A set can't have an unhashable value inside, such as
-            # a dict. Convert sets to tuples, which is fine, since we can't
-            # send them over RPC anyway.
+            # NOTE(danms, gibi) A set can't have an unhashable value inside,
+            # such as a dict. Convert the set to list, which is fine, since we
+            # can't send them over RPC anyway. We convert it to list as this
+            # way there will be no semantic change between the fake rpc driver
+            # used in functional test and a normal rpc driver.
             if iterable == set:
-                iterable = tuple
+                iterable = list
             return iterable([action_fn(context, value) for value in values])
 
     def serialize_entity(self, context, entity):
diff --git a/nova/tests/unit/objects/test_objects.py b/nova/tests/unit/objects/test_objects.py
index 07ed88f..5178da9 100644
--- a/nova/tests/unit/objects/test_objects.py
+++ b/nova/tests/unit/objects/test_objects.py
@@ -1013,6 +1013,10 @@ class TestObjectSerializer(_BaseTestCase):
         for thing in (1, 'foo', [1, 2], {'foo': 'bar'}):
             self.assertEqual(thing, ser.deserialize_entity(None, thing))
 
+    def test_serialize_set_to_list(self):
+        ser = base.NovaObjectSerializer()
+        self.assertEqual([1, 2], ser.serialize_entity(None, set([1, 2])))
+
     def _test_deserialize_entity_newer(self, obj_version, backported_to,
                                        my_version='1.6'):
         ser = base.NovaObjectSerializer()