[rabbitmq-discuss] Shovel Plugin For HA

Thu Oct 20 19:37:42 BST 2011

Maybe I misunderstand? :)

Given that I have a cluster of brokers used for a single geographical
location and each machine that publishes messages has a local broker
that pushes messages out to the central cluster:

The cluster is the upstream
The local brokers are the downstream

Or is it the other way around?

Thanks,
James

On Thu, Oct 20, 2011 at 11:26 AM, Simon MacMullen <simon at rabbitmq.com> wrote:
> On 20/10/11 15:24, James Carr wrote:
>>
>> Thanks, I tried it and it works advertised, but I feel like I may have
>> misunderstood it.
>
> Just to be clear, we are still talking about the federation exchange, right?
>
>> I've set it up and have messages published to a local exchange being
>> routed to an exchange on a central broker. however when the central
>> broker is down there's no local queuing of messages until it comes
>> back up.
>
> That should really be happening. I am assuming your local exchange is the
> upstream and the central exchange is the downstream. When the downstream
> connects to the upstream it should create a queue (with a name beginning
> "federation: " on the upstream. Can you see this in mgmt / rabbitmqctl? Of
> course, if you use the queue_expires parameter the upstream queue will
> expire eventually.
>
>> Of course, maybe I am just designing my topology wrong. Maybe instead
>> of separate exchanges per application I should just have one exchange,
>> shoveled out to the remote exchange and then multiple queues bound to
>> that exchange. The exchange per app was going to make things
>> heavyweight with the shovel plugin since I'd have to restart local
>> brokers for each new exchange, but with a single exchange, single
>> local queue and multiple remote queues might make things more
>> effecient.
>>
>> Maybe the federation plugin includes a backing queue that can be
>> switched on or am I  missing something?
>
> It is always on - even if the downstream does not disconnect then the
> upstream might publish messages faster than they can get sent across the
> link.
>
> Cheers, Simon
>
> --
> Simon MacMullen
> RabbitMQ, VMware
>