CODEWITHSUNDEEP
rabbitmq
stevie el
stevie el

Reputation: 76

How distributed should queues be in a RabbitMQ cluster?

Assume you have a small rabbitmq system of 3 nodes that is supposed to handle 100+ decently high volume queues in the same exchange. Given that queues only exist on the node they are created on (we're not using replicated, High Availability queues), what's the best way to create the queues? Is there any benefit to having the queues distributed among the cluster nodes, or is it better to keep them all on one node and have rmq do the routing?

Upvotes: 3

Views: 3687

Answers (2)

jrob
jrob

Reputation: 21

As part of a move towards redundancy and failover in an application I'm working on, I've just finished setting up a RabbitMQ cluster behind a proxy, and have all of my publishers and consumers connect via the proxy, which round robins connections to the individual nodes as they come in from the clients. Prior to upgrading RabbitMQ to 2.7.1, this seemed to pretty evenly distribute queues to the separate nodes, though this would of course depend pretty heavily on how your proxy balances the requests and when your clients try to connect (and declare a queue)...

Having said all that, I just upgraded to RabbitMQ 2.7.1, which was pretty painless, and gave us HA queues, which is a pretty big win for our apps. At any rate, if you're interested in the set up, and think it would be of benefit to your queue problem, I'd be happy to share the setup.

Upvotes: 2

scvalex
scvalex

Reputation: 15365

It depends on your application, really.

RabbitMQ is smart about sending messages, so it'll only send a message to a node in the cluster if

  1. a queue that holds that message resides on that node or
  2. if a consumer has connected to that node and has requested the message.

In general, you should aim to declare queues on the nodes on which both the publishers and the consumers for that queue will connect to. In other words, you should aim to connect publishers and consumers to the node that holds the queues they use. This assumes you're trying to conserve bandwidth used overall.

If you're using clustering to improve throughput (and you probably are), and you don't care about internal bandwidth used, you should aim to connect your publishers/consumers to the nodes in a balanced way and not worry about the internal routing mechanisms.

One last thing to think about is memory and disk-space. Queues store messages in main memory, and fallback to disk if that's insufficient. So, if you declare all your queues in one place, that'll result in one node that's "over-worked" and two nodes with memory to spare.

Upvotes: 3

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