diff --git a/helpers/ab-nginx.sh b/helpers/ab-nginx.sh
index c1ec770..8a038ad 100644
--- a/helpers/ab-nginx.sh
+++ b/helpers/ab-nginx.sh
@@ -30,10 +30,10 @@ NETWORK='nginx_network'
 SUBNET='172.31.254.0/24'
 HTTP_PORT=80
 HTTPS_PORT=443
-unset CONFIG_DIR
-unset SERVERS_DIR
-unset WEBROOT_DIR
-unset vmount
+CONFIG_DIR=""
+SERVERS_DIR=""
+WEBROOT_DIR=""
+volumeMounts=""
 
 ### functions