diff --git a/magnum/api/controllers/v1/container.py b/magnum/api/controllers/v1/container.py
index 8fb502addb..7b52ce68cc 100644
--- a/magnum/api/controllers/v1/container.py
+++ b/magnum/api/controllers/v1/container.py
@@ -291,7 +291,7 @@ class ContainersController(rest.RestController):
                 LOG.exception(_LE("Error while list container %(uuid)s: "
                                   "%(e)s."),
                               {'uuid': c.uuid, 'e': e})
-                containers[i].status = 'Unknown'
+                containers[i].status = objects.container.UNKNOWN
 
         return ContainerCollection.convert_with_links(containers, limit,
                                                       url=resource_url,
diff --git a/magnum/objects/container.py b/magnum/objects/container.py
index fefd460f40..84716892db 100644
--- a/magnum/objects/container.py
+++ b/magnum/objects/container.py
@@ -24,6 +24,7 @@ ERROR = 'Error'
 RUNNING = 'Running'
 STOPPED = 'Stopped'
 PAUSED = 'Paused'
+UNKNOWN = 'Unknown'
 
 
 @base.MagnumObjectRegistry.register
diff --git a/magnum/tests/unit/api/controllers/v1/test_container.py b/magnum/tests/unit/api/controllers/v1/test_container.py
index f815ffb429..a1a49b0270 100644
--- a/magnum/tests/unit/api/controllers/v1/test_container.py
+++ b/magnum/tests/unit/api/controllers/v1/test_container.py
@@ -253,7 +253,7 @@ class TestContainerController(api_base.FunctionalTest):
                          test_container['uuid'])
 
         self.assertEqual(actual_containers[0].get('status'),
-                         'Unknown')
+                         objects.container.UNKNOWN)
 
     @patch('magnum.conductor.api.API.container_show')
     @patch('magnum.objects.Container.get_by_uuid')