diff --git a/xos/openstack_observer/steps/sync_controller_networks.py b/xos/openstack_observer/steps/sync_controller_networks.py
index 1e7805f..ef238ee 100644
--- a/xos/openstack_observer/steps/sync_controller_networks.py
+++ b/xos/openstack_observer/steps/sync_controller_networks.py
@@ -69,7 +69,7 @@
         if (controller_network.network.template.name!='Private'):
             logger.info("skipping network controller %s because it is not private" % controller_network)
             # We only sync private networks
-            return
+            return SyncStep.SYNC_WITHOUT_RUNNING
         
         if not controller_network.controller.admin_user:
             logger.info("controller %r has no admin_user, skipping" % controller_network.controller)
diff --git a/xos/openstack_observer/syncstep.py b/xos/openstack_observer/syncstep.py
index 66225d0..7accbfa 100644
--- a/xos/openstack_observer/syncstep.py
+++ b/xos/openstack_observer/syncstep.py
@@ -45,6 +45,12 @@
         psmodel        Model name the step synchronizes
         dependencies    list of names of models that must be synchronized first if the current model depends on them
     """
+
+    # map_sync_outputs can return this value to cause a step to be marked
+    # successful without running ansible. Used for sync_network_controllers
+    # on nat networks.
+    SYNC_WITHOUT_RUNNING = "sync_without_running"
+
     slow=False
     def get_prop(self, prop):
         try:
@@ -128,6 +134,8 @@
             pass
 
         tenant_fields = self.map_sync_inputs(o)
+        if tenant_fields == SyncStep.SYNC_WITHOUT_RUNNING:
+            return
         main_objs=self.observes
         if (type(main_objs) is list):
             main_objs=main_objs[0]