Comment 8 for bug 1103195

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?

Even if the region is in an HA configuration, the cluster controller
will connect to localhost and therefore the region app server reached
will be the one on the same machine, and thus able to see the same
UUID.

Then we can probably get rid of the special cases for maas_url and
whatnot.

If this isn't suitable, then I suggest going with rvba's second
proposal:

> - we fix the two problems I mention above ( a): only accept the
> first controller to connect if it's connecting from localhost, b)
> update nodegroup.maas_url for the first controller if the
> controller does not connect from localhost).