Don’t know if this works with EC2 or just Fargate, but AWS now offers DNS-based service discovery which can be hooked into libcluster so you don’t have to rely on tags, etc. See Libcluster in docker on aws elastic beanstalk - can't create a cluster for details. Again, I only tried on Fargate and it was super-simple…dunno if that translates to raw EC2 instances or not.
