Akka remoting and Heroku

Question

I'm investigating the use of Scala/Play/Akka on Heroku and I'm curious about something. Suppose I have an application structured as a network of Akka actors. Some of the actors will be in-process with the web application itself, but I may want to set aside one or more nodes as dedicated Akka actors: for example, a group of cache manager actors.

To configure Akka remoting, I need to supply IP addresses in akka.conf. But since Heroku nodes are somewhat ephemeral, I won't know each node's address at the time I write the config file.

It might simplify things to have a central "registration" node, but even there, I won't know the IP address of that node in advance.

So how do my Akka nodes refer to each other on Heroku?

Answer 1

Heroku dynos can't talk directly to each other so you will have to use an external messaging system like RabbitMQ. There is a great article on the Heroku Dev Center about how to coordinate Akka Actors in this way:
https://devcenter.heroku.com/articles/scaling-out-with-scala-and-akka