Skip provisioning rabbitmq on CFGM when using external servers

as defined env.cfgm in testbed

Change-Id: Ie76e44f7e3a0861b614c7d29cd55f83ed2e057ce
Partial-Bug: 1571043

fabfile/config.py

@@ -27,8 +27,8 @@
     for key in env.passwords.keys():
         env.passwords.update({key+':22' : env.passwords[key]})
 
-# Set default rabbit role as cfgm.
-env.roledefs['rabbit'] = env.roledefs['cfgm']
+# Set default rabbit role
+env.roledefs['rabbit'] = []
 
 # Set default openstack role to empty list,
 # If env.roledefs['openstack'] is not set in the testbed.py

fabfile/tasks/rabbitmq.py

@@ -345,15 +345,20 @@ def join_rabbitmq_cluster(new_ctrl_host):
 @roles('build')
 def setup_rabbitmq_cluster(force=False):
     """Task to cluster the rabbit servers."""
+    amqp_roles = []
     rabbit_servers = get_from_testbed_dict('cfgm', 'amqp_hosts', None)
     if rabbit_servers:
         print "Using external rabbitmq servers %s" % rabbit_servers
-        return
-    # Provision rabbitmq cluster in cfgm role nodes.
-    amqp_roles = ['cfgm']
+    else:
+        # Provision rabbitmq cluster in cfgm role nodes.
+        print "Provisioning rabbitq in cfgm nodes"
+        amqp_roles = ['cfgm']
+
+    # Provision rabbitmq cluster in openstack on request
     if get_from_testbed_dict('openstack', 'manage_amqp', 'no') == 'yes':
         # Provision rabbitmq cluster in openstack role nodes aswell.
         amqp_roles.append('openstack')
+
     for role in amqp_roles:
         env.roledefs['rabbit'] = env.roledefs[role]