What is Federation Exchange in RabbitMQ and How to use it

Federated exchange differs from the federated queues. Exchanges replicate the flow of messages from one location to another.

In this setup, an exchange on the remote host connects to an upstream server’s queue where all messages are published.

In simple words “Federated exchanges replicate messages“.

this can do load balancing by adding one cluster for the producer and another cluster for the consumer
when we need to send the same message to several locations
Federation has several use cases, such as collecting messages from multiple clusters to a central cluster, distributing a queue’s load across multiple clusters, and migrating to another cluster without interrupting producers or consumers.

What is Upstream and Downstream?

Upstream servers are the servers towards messages that are originally published.

Downstream servers are where the messages get forwarded to.

Requirement

Know which one is your Upstream Server and DownStream Server
Enable :- rabbitmq-plugins enable rabbitmq_federation “On Downstream Server “
Must Have the same Exchange Name and Queue Name and binding on Both Servers.
Upstream Server Where Messages are Originally Published.
Downstream Server where the messages get forwarded to.

First, we are going to Enable the rabbitmq_federation Plugin on the Downstream Server.

After enabling we are going to see these Options on the Server.

Clicking on Federation Upstreams to configure it.

Here we are going to Enter Upstreams Server Details and Configure it.

Enter Name:- federation-policy
URI :- amqp://admin:guest@127.0.0.1:5672/

Example :- [amqp://Username : Password @ IPAddress : PORT ]

After Adding a new upstream.

Now to Check the Status

Now we have configured the Federation exchange. Next, add Policy.

Adding Policy

Add Name:- federation-policy
Pattern:- .federation_. “This pattern should match with Exchange Name.”
Federation :- federation-upstream-set : all