[rabbitmq-discuss] Debugging problems with federation plug in.
simon at rabbitmq.com
Wed Jun 25 08:13:07 BST 2014
On 24/06/2014 22:44, Dan Galewsky wrote:
> We have a federation with 4 nodes.
> We are continually fighting problems with messages making it to some
> nodes in the exchange and not to others.
> Current situation is that I can drop a message into the federated
> exchange and all three downstream nodes see my message.
> Messages can be sent to me from two of the nodes but not the third.
> They put a message into the federated exchange and the other two nodes
> see the message and my node does not.
What does the link status at your end say? You should have a link for
every (federated exchange, upstream) pair. Federation works on a pull
model so your node is responsible for getting messages from the upstream.
> Something I have noticed is that on the Queues tab - in the Parameters
> column of the Rabbit webapp - I see "D ARGS" for the nodes that can talk
> to me and only "D" on the node that is unable to talk to me.
The difference is one of version, recent versions of the federation
plugin set x-internal-purpose: federation so you can identify
federation-internal things. It should just mean that node is running an
older RabbitMQ, it should still work.
> And if I hover over the ARGS string in the UI - I get a hover label that
> says "x-internal-purpose: federation" which makes me think that somehow
> the other node and I are not federated (even though I can send them
> messages through the federated exchange).
Note that each federation link is unidirectional, for bidirectional
federation you have two links. So it can be working one way and broken
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