diff --git a/magnum_tempest_plugin/config.py b/magnum_tempest_plugin/config.py
index 5ba9645..bd8d6a2 100644
--- a/magnum_tempest_plugin/config.py
+++ b/magnum_tempest_plugin/config.py
@@ -39,7 +39,8 @@ MagnumGroup = [
                         'publicURL', 'adminURL', 'internalURL'],
                help="The endpoint type to use for the coe service."),
     cfg.StrOpt("docker_storage_driver",
-               help="Docker storage driver. Supported: devicemapper, overlay"),
+               choices=['devicemapper', 'overlay'],
+               help="Docker storage driver."),
     cfg.StrOpt("image_id",
                default="fedora-coreos-latest",
                help="Image id to be used for ClusterTemplate."),