Akka remote in docker container

Question

Some confusion I am facing about the proper configuration to set to be able to access to my akka application deployed into a docker container. Though I am running a virtualbox ubuntu VM, I would like at first to be able to access the container from this VM before forwarding ports on the VM host. application.conf:

akka {
  actor {
    provider = remote
  }
  remote {
    enabled-transports = ["akka.remote.netty.tcp"]
    netty.tcp {
      hostname = ${?HOSTNAME}       # what should it be? 0.0.0.0 or the assigned docker one like 172.17.0.x but unknown in advance
      port = ${?PORT}               # 800

      bind-hostname = ${?BIND_HOSTNAME} # 127.0.0.1 ?
      bind-port = ${?BIND_PORT}         # 800 ? xxxx ?

      # 30Mb max msg
      message-frame-size =  30000000b
      send-buffer-size =  30000000
      receive-buffer-size =  30000000b
      maximum-frame-size = 30000000b
    }
  }
  loggers = ["akka.event.slf4j.Slf4jLogger"]
  loglevel = "DEBUG"
  logging-filter = "akka.event.slf4j.Slf4jLoggingFilter"
}

my docker file that builds and runs the application properly according to the logs:

FROM openjdk:8u151

    # Env variables
    ENV SCALA_VERSION 2.12.4
    ENV SBT_VERSION 1.1.1

    # Scala expects this file
    RUN touch /usr/lib/jvm/java-8-openjdk-amd64/release

    # Install Scala
    # Piping curl directly in tar
    RUN \
      curl -fsL https://downloads.typesafe.com/scala/$SCALA_VERSION/scala-$SCALA_VERSION.tgz | tar xfz - -C /root/ && \
      echo >> /root/.bashrc && \
      echo "export PATH=~/scala-$SCALA_VERSION/bin:$PATH" >> /root/.bashrc

    # Mk app dir
    RUN mkdir /alor

    # Define working directory
    WORKDIR /alor

    # Add target packaged app
    COPY target/universal/stage/ /alor/

    # Expose ports
    EXPOSE 800
    EXPOSE 5150

    # Launch the app
    CMD ./bin/alor

after running the image, I tried to access the address 172.17.0.x:800 after inspecting the container but without anything being logged on the container console.

score 2 · Accepted Answer · answered Feb 28 '18 at 09:34

Found my own solution, don't know if it comes down to akka issue in the binding configuration or that the raw openjdk image hasn't internal binding for local network as I tried different ones such as bind-hostname = 127.0.0.1 bind-port=xxx but setting for example:

  hostname = 172.17.0.2   
  port = 800

  bind-hostname = 0.0.0.0
  bind-port = ""

makes the akka system reachable from the outside world with 172.17.0.2:800. The ip of the docker container can use internal network as well instead of guessing it

Akka remote in docker container

1 Answers1