The provider constructor requires a pass-through id parameter.

octodns/provider/rackspace.py

@@ -43,7 +43,7 @@ class RackspaceProvider(BaseProvider):
     SUPPORTS_GEO = False
     TIMEOUT = 5
 
-    def __init__(self, username, api_key, *args, **kwargs):
+    def __init__(self, id, username, api_key, *args, **kwargs):
         '''
         Rackspace API v1 Provider
 

tests/test_octodns_provider_rackspace.py

@@ -49,7 +49,7 @@ class TestRackspaceProvider(TestCase):
         self.maxDiff = 1000
         with requests_mock() as mock:
             mock.post(ANY, status_code=200, text=AUTH_RESPONSE)
-            self.provider = RackspaceProvider('test', 'api-key')
+            self.provider = RackspaceProvider(id, 'test', 'api-key')
             self.assertTrue(mock.called_once)
 
     def test_bad_auth(self):