aidanhs/socket-socat repository overview

⁠docker-socket-socat

A simple container to expose /var/lib/docker.sock on port 2375. Useful to hit the Docker daemon during docker build.

As of 1.8, names of containers are automatically inserted into /etc/hosts, so if you run this container with

docker run -d -v /var/run/docker.sock:/docker.sock --name dsocket aidanhs/socket-socat

you can have instructions like this in your Dockerfile

ENV DOCKER_HOST tcp://dsocket:2375
RUN docker ps

and it'll work!

This is great if you're using a Dockerfile to drive an Ansible playbook which uses the Docker connection plugin. Or for any build tool to drive Docker really - if your apps can run in a reproducible environment, why not your image build tools!? One amusing thought is to use a Dockerfile to run a bunch of other Dockerfiles - everything perfectly encapsulated.

⁠Security

Running this gives anyone on your machine root access.

If they have the ability to run arbitrary containers, they already had this.