/etc/maas/maas_local_celeryconfig_cluster.py is in maas-cluster-controller 1.2+bzr1373+dfsg-0ubuntu1~12.04.6.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | # UUID identifying the running cluster controller.
CLUSTER_UUID = None
|