Mosaic RabbitMQ upgrade to 4.0.3

Today we successfully completed our planned RabbitMQ Server upgrade from version 3.12.10 to 4.0.3.

We're happy to say that this major version upgrade went almost as smooth as we planned >=]. We opted for a Blue-Green deployment in this specific upgrade as it offered us the least disruption times.

Now all the existing definitions are migrated and unprocessed messages are federated into the new RabbitMQ Cluster, and all services re-connected.

What's new in the new major version?

You can read all about the highlights, breaking changes & compatibility notes at the RabbitMQ GitHub release notes.

One welcome change with this upgrade is the enabling of Khepri to replace Mnesia as a schema data store

Another major change is that classic queues are no longer replicated in a multi-node cluster (like ours), even though classic queues themselves are still supported.

Since quorum queues will guarantee high-availability of messages on the RabbitMQ Server, and considering the trend we see in reduced support for classic queues, we would like to encourage you to always work with quorum queues going forward.

When you use the @axinom/mosaic-message-bus library for setting up the message queues, they will already be created as quorum queues, and no further action is needed. However if your services are using other means for creating queues, please check if you're creating classic queues, and consider moving away to quorum queues. Always consider high-availability is not guaranteed for classic queues.

If you have any questions or experience any issues, please do not hesitate to reach out to our support.