<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi,<div><br><div><div>On 9 May 2013, at 21:10, k.madnani84 wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div> Is the question whether the connections federation makes to upstream brokers<br>need to be handled 'specially' if they access the upstream via HAProxy?<br>Yes exactly i want to know how federation communicates with upstreams and<br>presence of HAProxy in between federation and upstream will make any<br>difference or we need to communicate as it is?<br><br></div></blockquote></div><br></div><div>Federation uses ordinary AMQP connections to communicate with upstream nodes. For each upstream node, there will be a connection. Load balancing should not be a problem in theory, because RabbitMQ clusters share information about queues and federation uses a queue internally (on the upstream node) known as the <i>upstream queue</i>, which the downstream connections are consuming from. As per the reliability guide (<a href="http://www.rabbitmq.com/reliability.html">http://www.rabbitmq.com/reliability.html</a>):</div><div><br></div><div>"Federation will automatically distribute links across
the downstream cluster and fail them over on failure of a downstream
node. In order to connect to a new upstream when an upstream
node fails you can specify multiple redundant URIs for an upstream,
or connect via a TCP load balancer."</div><div><br></div><div>HTH</div><div><br></div><div>Cheers,</div><div>Tim</div></body></html>