[rabbitmq-discuss] RabbitMQ - can we make use policies as load balancing in cluster?

[Michael Klishin]

On 18 Oct 2013, at 11:40, Rajasekhar P <sekhar434145 at gmail.com> wrote:

> Can you please clarify me this as well,  with policies only we can achieve mirrored queues right?

Policies is a way to add queue attributes in a centralised way. Instead of your apps knowing how to set up mirroring or
replication, you may choose to configure a policy to do it instead.

A policy is a named pattern, e.g. ^log.*, which matches queue names. For the names that match, policy is applied
(extra attributes are added).

At the moment, policies are used for two RabbitMQ features: mirrored queues (replication of message contents) and
federated exchanges (primarily useful for WAN-friendly asynchronous replication).

> if not, how mirrored queues and policies are different?

See above.

> In the previous mail you have mentioned something about federated exchanges. Can we achieve load balancing with this?

Not really. Federated exchanges allow you replicate a stream of messages published to exchange X across N nodes
or clusters.

Federated queues are different. They allow load balancing of a single queue between nodes, however,
this is a new feature that's only available in RabbitMQ 3.2 (nightlies) and need some documentation
improvements.

Feel free to give nightly builds a try but wait for 3.2 final release before deploying into production.

> And how exactly it is different from Mirrored queues? Currently we are using 3.1.3,  can you please share docs related federation?

http://www.rabbitmq.com/federation.html

Initial federated queues docs:
http://next.rabbitmq.com/federated-queues.html

MK