diff --git a/zun/common/keystone.py b/zun/common/keystone.py
index 377591186..cf4e27541 100644
--- a/zun/common/keystone.py
+++ b/zun/common/keystone.py
@@ -38,8 +38,9 @@ class KeystoneClientV3(object):
     def auth_url(self):
         # FIXME(pauloewerton): auth_url should be retrieved from keystone_auth
         # section by default
-        return CONF[ksconf.CFG_LEGACY_GROUP].www_authenticate_uri.replace(
-            'v2.0', 'v3')
+        url = CONF[ksconf.CFG_LEGACY_GROUP].www_authenticate_uri or \
+            CONF[ksconf.CFG_LEGACY_GROUP].auth_uri
+        return url.replace('v2.0', 'v3')
 
     @property
     def auth_token(self):
diff --git a/zun/conf/keystone.py b/zun/conf/keystone.py
index 8c422007e..4394fd277 100644
--- a/zun/conf/keystone.py
+++ b/zun/conf/keystone.py
@@ -25,8 +25,6 @@ def register_opts(conf):
     ka_loading.register_auth_conf_options(conf, CFG_GROUP)
     ka_loading.register_session_conf_options(conf, CFG_GROUP)
     conf.set_default('auth_type', default='password', group=CFG_GROUP)
-    conf.import_opt('www_authenticate_uri', 'keystonemiddleware.auth_token',
-                    group=CFG_LEGACY_GROUP)
 
 
 def list_opts():