add cluster definition for gtws
diff --git a/salt/control/cluster/openstack_gateway_single.yml b/salt/control/cluster/openstack_gateway_single.yml
index c1a4588..1b30b6c 100644
--- a/salt/control/cluster/openstack_gateway_single.yml
+++ b/salt/control/cluster/openstack_gateway_single.yml
@@ -14,5 +14,5 @@
           node:
             gtw01:
               provider: kvm01.${_param:cluster_domain}
-              image: ${_param:salt_control_trusty_image}
+              image: ${_param:salt_control_xenial_image}
               size: openstack.gateway