How to schedule a global period Akka job across multiple processes?

Question

I'm using Akka in Play Framework instead of a Job, to schedule code to run every X seconds. I have a sort of cluster (running on Heroku, currently on 1 dyno but there might be a few concurrent instances occasionally).

Is there an easy way to make the "job" run every N seconds globally in the entire cluster? I know that Quartz supports out-of-process storage/sync mechanisms e.g. a DB - can I use something similar in Scala?

This is the actor setup that is run on Play start:

object Global extends GlobalSettings {

  override def onStart(app: Application) {
    val monitorActor = Akka.system.actorOf(Props[MonitorLoadJob], name = "monitorLoad")
    Akka.system.scheduler.schedule(0 seconds, 10 seconds, monitorActor, Tick)
  }
}

Answer 1

Check out ClusterSingletonManager.

For some use cases it is convenient and sometimes also mandatory to ensure that you have exactly one actor of a certain type running somewhere in the cluster.

Some examples:

• single point of responsibility for certain cluster-wide consistent decisions, or coordination of actions across the cluster system

It requires running Akka Cluster but it's made for this type of scenario.