diff --git a/manifests/proxy.pp b/manifests/proxy.pp
index af7c6ffa..6382ef57 100644
--- a/manifests/proxy.pp
+++ b/manifests/proxy.pp
@@ -253,6 +253,7 @@
     $auth_type = 'keystone'
   } else {
     warning('no auth type provided in the pipeline')
+    $auth_type = undef
   }
 
   if $pipeline[-1] != 'proxy-server' {