[Rdo-list] rdo-manager hostname issues with rabbitmq

James Slagle jslagle at redhat.com
Thu Apr 30 17:15:49 UTC 2015

On Thu, Apr 30, 2015 at 12:22:04PM -0400, Lars Kellogg-Stedman wrote:
> On Thu, Apr 30, 2015 at 08:15:35AM -0400, James Slagle wrote:
> > For baremetal, I've added some notes to the docs to hopefully cover the
> > requirements.
> I'm not familiar with AMQP.  Is there a particular reason why rabbitmq
> is so sensitive to hostname issues?  I was surprised to run into this
> with a packstack install the other day, especially given that
> packstack configures everything uses ip addresses rather than names.
> rabbitmq seems to perform some sort of reverse-lookup of the hostname,
> and there was a stale dns entry out there that it was picking up.
> This wouldn't have caused a problem for anything else (because the
> entire configuration is based on ip addresses rather than hostnames),
> but it prevented rabbitmq from starting up correctly.
> Is there any chance that we should also be pursuing this as a bug in
> rabbitmq?  Or is there a configuration we can tweak in rabbitmq that
> will make it less sensitive to hostname issues?


For this particular case anyway, it took me a little while to reproduce the
issue. Eventually I realized that if I set a hostname, then logged out and
then back in prior to installing the undercloud, I could never reproduce an
issue. That led me to believe it was environment related, and further, caused

grep'ing through the rabbitmq-server code, I saw that:
uses the $HOSTNAME value.

In my earlier email I said that rabbitmq-server sources rabbitmq-env (which is
true), but the actual problem I think is that rabbitmqctl also sources
rabbitmq-env, and puppetlabs-rabbitmq calls rabbitmqctl all over the place.

So, honestly, this could be a bug in rabbitmq-env, I'm not sure what the
accepted expectations are around $HOSTNAME, if there even are any. Note though
that rabbitmq-env also has it's *own* configuration file where a hostname could
be set as well.

-- James Slagle

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