diff --git a/metadata/service/volume/local.yml b/metadata/service/volume/local.yml
index 96a0461..bfa8020 100644
--- a/metadata/service/volume/local.yml
+++ b/metadata/service/volume/local.yml
@@ -52,5 +52,5 @@
       cache:
         engine: memcached
         members:
-          host: ${_param:single_address}
+          - host: ${_param:single_address}