Docker Tips

Note that Docker runs mainly on Linux 64-bit systems, although some ports may be available for other platforms.

Note to install latest Docker (Ubuntu)

On Debian systems, you can install Docker with…

sudo apt-get install lxc-docker

Or see docker.com for other platforms).
For Ubuntu, since March 3^rd, 2015 (Docker 1.5.x), you may have to use…

wget -qO- https://get.docker.io/gpg | sudo apt-key add -
sudo sh -c "echo deb http://get.docker.io/ubuntu docker main > /etc/apt/sources.list.d/docker.list"
sudo apt-get update
sudo apt-get install lxc-docker

.. to get the last version.

Docker Configuration

It is recommended to use docker version 1.5.x or higher.

When docker is installed, make sure to obtain a Docker Linux image (e.g. Ubuntu), so you can use it later as a base image for Roboconf agent images.
For example, run the following command:

docker pull ubuntu

Configure the TCP port for Docker Containers

Roboconf needs Docker to be available on a TCP port.
To enable it, edit /etc/default/docker, and define DOCKER_OPTS there.

# Make Docker listen on TCP port 4243 (along with local Unix socket)
DOCKER_OPTS="-H=tcp://0.0.0.0:4243 -H unix:///var/run/docker.sock"

Then, simply restart docker.

sudo stop docker
sudo start docker

Some Docker Commands

Here is a reminder of some Docker commands.

To list docker images:
docker images

To remove a docker image:
docker rmi <image-ID>

To run interactively a docker image (thus launching a container):
docker run -i -v /tmp:/roboconf -t <image-ID> /bin/bash

Note: the -v option is used there to share the local “/tmp” as “/roboconf” in the container, which is useful to exchange files.

To list running docker containers:
docker ps (or, to list them all, “docker ps -a”)

to attach a shell script to a running container:
docker exec -ti <container-ID> /bin/bash

To remove a docker container:
docker rm <container-ID>

To remove all exited containers:
docker ps -a | grep Exit | cut -d ‘ ‘ -f 1 | xargs docker rm