Akka cluster - Association with remote system has failed...Reason: [Association failed]

Question

I have a simple POC with two actors:

public final class Task1Actor extends AbstractLoggingActor {
  public Task1Actor() {
    final UnitPFBuilder<Object> builder = ReceiveBuilder.create()
        .matchAny(message -> {
          log().warning("Received unknown message: {}", message);
          unhandled(message);
        });
    receive(builder.build());
  }

  @Override
  public void preStart() throws Exception {
    IntStream.range(0, 5).forEach(i -> {
      final ActorRef actor = context().actorOf(Props.create(Task2Actor.class));
      actor.tell(RandomStringUtils.randomAlphabetic(10), self());
    });
  }
}

---

public final class Task2Actor extends AbstractLoggingActor {
  public Task2Actor() {
    final UnitPFBuilder<Object> builder = ReceiveBuilder.create()
        .match(String.class, this::process)
        .matchAny(message -> {
          log().warning("Received unknown message: {}", message);
          unhandled(message);
        });
    receive(builder.build());
  }

  private void process(final String message) {
    log().debug("Processing message: {}", message);
    // Do something useful here in the (not-so far) future
  }
}

This is the main class:

final class ClusterSample {
  public static void main(final String... args) throws Exception {
    ClusterSample.start(2251);
    ClusterSample.start(2252);
    ClusterSample.start(0);
  }

  private static void start(final int port) {
    final Config config = ConfigFactory.parseString(String.format("akka.remote.netty.tcp.port = %s", port))
        //.withFallback(ConfigFactory.parseString(String.format("akka.cluster.roles = [%s]", role)))
        .withFallback(ConfigFactory.load("cluster"));
    ActorSystem system = ActorSystem.create("ClusterSystem", config);
    system.actorOf(Props.create(Task1Actor.class));
  }
}

...and these are my configuration files (application.conf and cluster.conf respectively):

akka {
  actor {
    default-dispatcher { throughput = 5 }
    provider = cluster
  }

  cluster {
    seed-nodes = [ "akka.tcp://[email protected]:2551", "akka.tcp://[email protected]:2552" ]
    # roles = ["role"]
  }

  remote {
    log-remote-lifecycle-events = off
    netty.tcp {
      hostname = 127.0.0.1
      port = 0
    }
  }

  loggers = [ "akka.event.slf4j.Slf4jLogger" ]

  logging-filter = "akka.event.slf4j.Slf4jLoggingFilter"

  loglevel = DEBUG
}

---

include "application"

akka.cluster.min-nr-of-members = 2

akka.cluster.role {
  watson.min-nr-of-members = 2
}

akka.actor.deployment {
}

What I'm trying to achieve here is to "form a cluster" from an already established flow. So I used to have those actors (can be any flow really) and now I'm trying to make them work in (or as) a cluster. I just started reading about it so I'm not very familiar with this.

The errors I'm getting are:

03-09-2017 16:52:43.749 |- DEBUG in Task2Actor:88 [ClusterSystem-akka.actor.default-dispatcher-20] - Processing message: GCGboeqRKJ
03-09-2017 16:52:43.749 |- DEBUG in Task2Actor:88 [ClusterSystem-akka.actor.default-dispatcher-21] - Processing message: ykhePhziFT
03-09-2017 16:52:43.749 |- DEBUG in Task2Actor:88 [ClusterSystem-akka.actor.default-dispatcher-2] - Processing message: SFvnRAlGgg
03-09-2017 16:52:43.753 |- DEBUG in Task2Actor:88 [ClusterSystem-akka.actor.default-dispatcher-21] - Processing message: bMgBtCzWCI
03-09-2017 16:52:43.753 |- DEBUG in Task2Actor:88 [ClusterSystem-akka.actor.default-dispatcher-20] - Processing message: ifoOOmqbbv
03-09-2017 16:52:43.753 |- DEBUG in Task2Actor:88 [ClusterSystem-akka.actor.default-dispatcher-2] - Processing message: ZekwWXmmSQ
03-09-2017 16:52:43.754 |- DEBUG in Task2Actor:88 [ClusterSystem-akka.actor.default-dispatcher-21] - Processing message: MqXGoSQSzU
03-09-2017 16:52:43.754 |- DEBUG in Task2Actor:88 [ClusterSystem-akka.actor.default-dispatcher-20] - Processing message: NrdVYAFgrR
03-09-2017 16:52:43.754 |- DEBUG in Task2Actor:88 [ClusterSystem-akka.actor.default-dispatcher-2] - Processing message: GsjyIsxetC
03-09-2017 16:52:43.754 |- DEBUG in Task2Actor:88 [ClusterSystem-akka.actor.default-dispatcher-21] - Processing message: LpVNmbriXO
03-09-2017 16:52:43.754 |- DEBUG in Task2Actor:88 [ClusterSystem-akka.actor.default-dispatcher-20] - Processing message: HCFzOjJwnO
03-09-2017 16:52:43.755 |- DEBUG in Task2Actor:88 [ClusterSystem-akka.actor.default-dispatcher-2] - Processing message: iqflQMSeJF
03-09-2017 16:52:43.755 |- DEBUG in Task2Actor:88 [ClusterSystem-akka.actor.default-dispatcher-21] - Processing message: HlyMdMJfUs
03-09-2017 16:52:43.755 |- DEBUG in Task2Actor:88 [ClusterSystem-akka.actor.default-dispatcher-20] - Processing message: jlwxzLmRsF
03-09-2017 16:52:43.755 |- DEBUG in Task2Actor:88 [ClusterSystem-akka.actor.default-dispatcher-2] - Processing message: XPSmMYekCs
03-09-2017 16:52:43.794 |-  WARN in ReliableDeliverySupervisor:78 [ClusterSystem-akka.actor.default-dispatcher-20] - Association with remote system [akka.tcp://[email protected]:2552] has failed, address is now gated for [5000] ms. Reason: [Association failed with [akka.tcp://[email protected]:2552]] Caused by: [Connection refused: /127.0.0.1:2552]
03-09-2017 16:52:43.794 |-  WARN in ReliableDeliverySupervisor:78 [ClusterSystem-akka.actor.default-dispatcher-21] - Association with remote system [akka.tcp://[email protected]:2552] has failed, address is now gated for [5000] ms. Reason: [Association failed with [akka.tcp://[email protected]:2552]] Caused by: [Connection refused: /127.0.0.1:2552]
03-09-2017 16:52:43.794 |-  WARN in ReliableDeliverySupervisor:78 [ClusterSystem-akka.actor.default-dispatcher-20] - Association with remote system [akka.tcp://[email protected]:2551] has failed, address is now gated for [5000] ms. Reason: [Association failed with [akka.tcp://[email protected]:2551]] Caused by: [Connection refused: /127.0.0.1:2551]
03-09-2017 16:52:43.794 |-  WARN in ReliableDeliverySupervisor:78 [ClusterSystem-akka.actor.default-dispatcher-2] - Association with remote system [akka.tcp://[email protected]:2551] has failed, address is now gated for [5000] ms. Reason: [Association failed with [akka.tcp://[email protected]:2551]] Caused by: [Connection refused: /127.0.0.1:2551]
03-09-2017 16:52:43.795 |-  WARN in ReliableDeliverySupervisor:78 [ClusterSystem-akka.actor.default-dispatcher-21] - Association with remote system [akka.tcp://[email protected]:2551] has failed, address is now gated for [5000] ms. Reason: [Association failed with [akka.tcp://[email protected]:2551]] Caused by: [Connection refused: /127.0.0.1:2551]
03-09-2017 16:52:43.796 |-  WARN in ReliableDeliverySupervisor:78 [ClusterSystem-akka.actor.default-dispatcher-2] - Association with remote system [akka.tcp://[email protected]:2552] has failed, address is now gated for [5000] ms. Reason: [Association failed with [akka.tcp://[email protected]:2552]] Caused by: [Connection refused: /127.0.0.1:2552]

I'm executing this on the same machine and nothing is using those ports...guaranteed. I have all the dependencies in my Gradle config, but still, I can't make it to work without issues.

Answer 1

Turns out I was using different port numbers; 2252 and 2251 in the Java code and 2552 and 2551 in the Akka configuration.

Correcting that will make the errors go away...but still, if I print out the actors' path I don't see it like akka.tcp://. . . but akka:// . . ., so I would assume the whole cluster thing is not working either. A different story and maybe another question.