[rabbitmq-discuss] Federation connections, VIPs, and queues

Wed Dec 12 17:29:14 GMT 2012

On 10/12/12 21:17, Matt Pietrek wrote:
> I realize this is a somewhat esoteric question and apologize for the
> complexity.

I don't think it's too bad. At least you're clear :-)

> We're still on 2.8.7 for a while, although my guess is that
> federation in 3.0 won't drastically change the answer.

Correct.

<snip>

> I'm trying to understand this behavior. It's almost as if the federation
> logic is burrowing underneath my VIP and discovering the actual node
> names. In my naive understanding, I'd expect that the use of VIPs would
> hide away the primary/alternate nodes.

This is the "local_nodename". See the documentation at:

http://previous.rabbitmq.com/federation.html#configuration

...in particular "The default is constructed from the Erlang node and 
the machine's fully-qualified domain name". So it has no idea about the VIP.

But just setting local_nodename explicitly on all your nodes should sort 
you out.

> *Question 2:*
> In a related vein, looking at the Exchanges I see exchanges like this:
>
> federation: skytap -> rabbit at slave A
> federation: skytap -> rabbit at slave-alternate B
>
> What do the A/B signify?

Internal workings of the federation mechanism ;-)

See

http://hg.rabbitmq.com/rabbitmq-federation/file/d64c99562b9a/README-hacking#l40

for a brief explanation.

Cheers, Simon

-- 
Simon MacMullen
RabbitMQ, VMware