Comment 3 for bug 1104215

> > To ensure that we accept as "master" only the cluster controller
> > on the local machine, can the region compare the UUID it's given
> > against the UUID it can see on the filesystem?
>
> A simpler way (which we already use to know if we need to update
> nodegroup.maas_url or not when a cluster connects) is to see if the
> cluster connects from 'localhost' or a remote host.

Is nodegroup.maas_url the URL that the cluster uses to talk to the
region? I can't remember the reason we don't update maas_url if the
cluster connects from localhost.

Also, connecting from localhost is a very weak form of authentication.
Presumably the cluster UUID is protected by filesystem permissions,
and so gives us a stronger way to verify the cluster.