add a reference to #156

we ensure we call 'db sync' scripts only once.

manifests/identity.pp

@@ -528,6 +528,9 @@ class cloud::identity (
   # Note(EmilienM):
   # We check if DB tables are created, if not we populate Keystone DB.
   # It's a hack to fit with our setup where we run MySQL/Galera
+  # TODO(Gonéri)
+  # We have to do this only on the primary node of the galera cluster to avoid race condition
+  # https://github.com/enovance/puppet-cloud/issues/156
   exec {'keystone_db_sync':
     command => '/usr/bin/keystone-manage db_sync',
     unless  => "/usr/bin/mysql keystone -h ${keystone_db_host} -u ${encoded_user} -p${encoded_password} -e \"show tables\" | /bin/grep Tables"