Yes, we have a pool of Elixir + Phoenix servers behind a classic Amazon Elastic Load Balancer (set to TCP/SSL mode, not HTTP/HTTPS, or else WebSockets don't work).

Hmmm cool. How are you deploying Phoenix?

Right now we're using Edeliver and Distillery. We're planning to containerize things soon, so I'm not sure what the toolchain will look like then, but if you have long-lived servers then Edeliver is great.