diff --git a/lib/nova b/lib/nova
index f423b57..7b364a6 100644
--- a/lib/nova
+++ b/lib/nova
@@ -601,8 +601,8 @@
     if is_service_enabled n-novnc || is_service_enabled n-xvnc || [ "$NOVA_VNC_ENABLED" != False ]; then
         # Address on which instance vncservers will listen on compute hosts.
         # For multi-host, this should be the management ip of the compute host.
-        VNCSERVER_LISTEN=${VNCSERVER_LISTEN=$NOVA_SERVICE_LOCAL_HOST}
-        VNCSERVER_PROXYCLIENT_ADDRESS=${VNCSERVER_PROXYCLIENT_ADDRESS=$NOVA_SERVICE_LOCAL_HOST}
+        VNCSERVER_LISTEN=${VNCSERVER_LISTEN:-$NOVA_SERVICE_LOCAL_HOST}
+        VNCSERVER_PROXYCLIENT_ADDRESS=${VNCSERVER_PROXYCLIENT_ADDRESS:-$NOVA_SERVICE_LOCAL_HOST}
         iniset $NOVA_CPU_CONF vnc server_listen "$VNCSERVER_LISTEN"
         iniset $NOVA_CPU_CONF vnc server_proxyclient_address "$VNCSERVER_PROXYCLIENT_ADDRESS"
     else