kluster

Dockerized Akka cluster.

This is minimal application of an akka cluster running on docker.

For more information see kluster and kluster updates.

building and developing

The command below builds the kluster container and starts a cluster with three nodes: kluster1, kluster2 and kluster3.

./run.sh

If you run docker ps you should see the three nodes running

CONTAINER ID  IMAGE    PORTS              NAMES
e6736ffb43f9  kluster  2550/tcp, 8080/tcp kluster3
57010bcd1afe  kluster  2550/tcp, 8080/tcp kluster2
1df1583dfb4f  kluster  2550/tcp, 8080/tcp kluster1

You can check the logs of a single node running docker logs, for example:

docker logs -f kluster1

To kill the kluster run

./run.sh -k

To recompile the code and redeploy the cluster execute:

./run.sh -f

You can remove a node from the cluster using the -r option. For example, to remove kluster2, run:

./run.sh -r 2

Use the -a COUNT option to add new nodes to the cluster. For example, to add 2 new nodes to the cluster, run:

./run.sh -a 2

The nodes run the akka http manager api. The containers have installed curl and jq so it's possible to trigger the api via docker exec. For example:

docker exec -ti kluster1 curl http://localhost:8558/cluster/members | jq .

The response of the command above is similar to this

{
  "leader": "akka.tcp://kluster@kluster1:2550",
  "members": [
    {
      "node": "akka.tcp://kluster@kluster1:2550",
      "nodeUid": "728916369",
      "roles": [
        "cruncher",
        "dc-default"
      ],
      "status": "Up"
    },
    {
      "node": "akka.tcp://kluster@kluster2:2550",
      "nodeUid": "-435323710",
      "roles": [
        "cruncher",
        "dc-default"
      ],
      "status": "Up"
    },
    {
      "node": "akka.tcp://kluster@kluster3:2550",
      "nodeUid": "162020309",
      "roles": [
        "cruncher",
        "dc-default"
      ],
      "status": "Up"
    }
  ],
  "oldest": "akka.tcp://kluster@kluster1:2550",
  "oldestPerRole": {
    "cruncher": "akka.tcp://kluster@kluster1:2550",
    "dc-default": "akka.tcp://kluster@kluster1:2550"
  },
  "selfNode": "akka.tcp://kluster@kluster1:2550",
  "unreachable": []
}