We used the stock AMI. I would not be surprised if we had a configuration issue, but we spent a lot of time trying to debug it and were never able to find the root cause of the issue.

yep, we were using Amazon ECS-Optimized Amazon Linux AMI, docker and agent should've matched there. It was strange behavior, either all agents were connected or most of them were disconnected at the same time...

How did you first discover the bug? Did your deploys just start failing in an obvious way, or did your instances disappear (from ECS's perspective)?

I'm wondering if Elastic Beanstalk is hiding this from us in some way. Or maybe just has a workaround built in?

Yes. This is pretty much what we saw.

We deployed K8S on AWS (I'm a dev at Appuri). Like Bilal mentioned we run pretty much everything on AWS, so it was an easy decision.

If you are still interested in trying Azure, shoot me an email (thmacie at microsoft dot com). I'll see if we can fix your problem.