Blue Green Deployment

[4sudiptodas]

We have a RMQ cluster which we plan to upgrade. It's behind an AWS target group which is infront of a load balancer. The publisher and consumer uses the same DNS name to publish/consume. Is blue green possible with this approach? If not what architecture changes we should make it in app or in RMQ. The sequence of messages is important.

Previously it was a full cluster stop and upgrade process.

[michaelklishin]

@4sudiptodas why wouldn't it be possible?

As long as you can export definitions, (possibly transformthem), and import definitions into the new cluster, plugin queue federation links can connect to the new cluster from the original one, everything in the Blue/Green deployment guide should work regardless of you have in front of your load balancer.

[michaelklishin]

@4sudiptodas when applications are moved to the new (green) cluster and federation links are running, you potentially can end up with a competing consumers scenario, even though queue federation links use negative consumer priorities by design.

The only general recommendation I have is moving your consumers first, then setting up queue federation, which will move messages to the new cluster because no local consumers will be present.

Then move publishers as you see fit.

Queue federation links have limited throughput compared to Java, .NET, Rust, Go clients, so if the rates are too high for them (say, 10s of thousands of messages), the only recommendation I can think of is to use streams, where reads are repeatable and non-destructive.