Akka Cluster Connection Refused Between Machines

Akka Libraries Akka Cluster
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1

I am crossposting this issue between here and StackOverflow (https://stackoverflow.com/questions/64108688/akka-cluster-connection-refused-between-machines) since this is specific to Akka.

I am attempting to make a project using Akka Clustering, and have been using the akka-cluster-sample-scala from Lightbend(https://github.com/akka/akka-samples/tree/2.6/akka-sample-cluster-scala) as a base. As it lacks much direct information on connecting across a network, I modified the application.conf to look more like this:

akka {
  actor {
    provider = cluster

    serialization-bindings {
      "sample.cluster.CborSerializable" = jackson-cbor
    }
  }
  remote {
    artery {
      canonical.hostname = "127.0.0.1"
      canonical.port = 0
    }
  }
  cluster {
    seed-nodes = [
      "akka://ClusterSystem@131.194.71.132:25251",
      "akka://ClusterSystem@131.194.71.132:25252",
      "akka://ClusterSystem@131.194.71.133:25251",
      "akka://ClusterSystem@131.194.71.133:25252"]
    downing-provider-class = "akka.cluster.sbr.SplitBrainResolverProvider"
  }
}

When run across these two machines, Akka fails to be able to connect over TCP between them, leading to the following warnings:

[info] [2020-09-28 14:34:37,877] [WARN] [akka.stream.Materializer] [] [ClusterSystem-akka.actor.default-dispatcher-5] - [outbound connection to [akka://ClusterSystem@131.194.71.132:25251], control stream] Upstream failed, cause: StreamTcpException: Tcp command [Connect(131.194.71.132:25251,None,List(),Some(5000 milliseconds),true)] failed because of java.net.ConnectException: Connection refused

Is there anything notably wrong that may be causing this, or something more specifically needing to be reconfigured in order to allow connection over TCP between these machines?

2

canonical.hostname cannot be 127.0.0.1 and port 0 but must be configured to be the public ip/hostname and port that other nodes can use to reach the node.

So for 131.194.71.132:25251 it needs to be 131.194.71.132 and 25251 for example.

2 Likes
3

Thank you so much for taking the time to respond. This just helped immensely.