How to connect to a zeromq server running inside a docker container?

Docker Engine General
1

I installed boot2docker as explained on the docker website. Here are some command runs to show that I have things installed correctly:

$$:~ kv$ boot2docker start
    Waiting for VM and Docker daemon to start...
    ...................ooo
    Started.
    Writing /Users/kvantum/.boot2docker/certs/boot2docker-vm/ca.pem
    Writing /Users/kvantum/.boot2docker/certs/boot2docker-vm/cert.pem
    Writing /Users/kvantum/.boot2docker/certs/boot2docker-vm/key.pem
    Your environment variables are already set correctly.

    $$:~ kv$ docker images
    REPOSITORY  TAG     IMAGE ID        CREATED             VIRTUAL SIZE
    ubuntu     14.04   b39b81afc8ca        11 days ago         188.3 MB
    hello-world  latest e45a5af57b00        3 weeks ago         910 B

After this, I ran the following command:

docker run -t -i ubuntu:14.04 /bin/bash

Inside the container, I installed zeromq, and started a zeromq server on port 5555 using tcp.

My questions are following:

  1. If I exit out of the container, will it save all the work I do inside it?

  2. I have no idea how to connect to the server running on port 5555. I read something about exposing a port, but I am not sure how to go about doing that. I did an ifconfig inside the container, and tried to connect to the server from the host like this:

    $$:~ kv$ ./zmq_client tcp://container_ip:5555

This did not work. Can someone please lists the steps I need to take in order to connect to the server running within the container.

For completion sake, I am providing the list of my environment variables:

 TERM_PROGRAM=Apple_Terminal
    TERM=xterm-256color
    SHELL=/bin/bash
    TMPDIR=/var/folders/km/5kbpdx4s7cg4rmyc6d5q9l9r0000gq/T/
    DOCKER_HOST=tcp://192.168.109.103:2376
    Apple_PubSub_Socket_Render=/tmp/launch-1tWMHJ/Render
    TERM_PROGRAM_VERSION=326
    OLDPWD=/Users
    TERM_SESSION_ID=262CBC8B-0A74-4B70-9F28-D9FA51FF713C
    USER=kv
    SSH_AUTH_SOCK=/tmp/launch-ZTWNGL/Listeners
    __CF_USER_TEXT_ENCODING=0x1F7:0:0
    DOCKER_TLS_VERIFY=1
    __CHECKFIX1436934=1
    PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/opt/X11/bin
    PWD=/Users/kv
    DOCKER_CERT_PATH=/Users/kv/.boot2docker/certs/boot2docker-vm
    HOME=/Users/kv
    SHLVL=1
    LOGNAME=kv
    LC_CTYPE=UTF-8
    DISPLAY=/tmp/launch-rco9zt/org.macosforge.xquartz:0
    _=/usr/bin/env

One last question I have is about code performance. So within my Mac OS X, I have a docker container running (which runs Ubuntu). If I run the application, like a zeromq based server inside the container, will it not be slower as compared to running it on Mac OS X directly. Please explain the benefits of using docker in such a scenario…

2

I think you’ll find the userguide useful for starting your container with the port mapping to expose zeromq on the host only network (use boot2docker ip to find the vm’s IP)