Comment 22 for bug 653405

I received this very detailed response from Simon MacMullen of RabbitMQ, reposting here w/ his permission.

It seems that given the response below, neither issue will be easily fixable in versions of RabbitMQ prior to 2.2.0 or older versions of erlang.

I think this one will probably have to be a Won't Fix for versions prior to those mentioned below.

Marking Triaged.

Note that there is a merge request for the version of erlang that should fix the problem in bug #690068

=== Paste from email ===

On 25/01/11 14:31, Clint Byrum wrote:
> This bug has been reported in Ubuntu. Hopefully you guys already have it
> in the internal bug tracker:
>
> https://bugs.launchpad.net/ubuntu/+source/rabbitmq-server/+bug/653405

Hi Clint. There are two independent bugs being reported there:

1) RabbitMQ 1.7.2 fails to start when the hostname has changed.
2) RabbitMQ 1.7.2 fails to start when the hostname cannot be resolved.

The first issue is caused by the fact that we use Erlang's database,
Mnesia internally, and that stores the hostname everywhere (since it's
designed for distributed use).

RabbitMQ 2.2.0 contains a workaround for this - the path to Mnesia now
contains the hostname, so if the hostname changes the old database will
not be found and a new one will be created. I'm not absolutely sure
where that was introduced between 1.7.2 and 2.2.0.

The second issue is an issue with Erlang's port mapper; epmd. We depend
on this (any Erlang app will), and it won't start if the hostname cannot
be resolved. This bug appears to exist in Erlang R13B3 and be fixed in
R14B. Again, I'm not sure exactly where the fix was introduced.