Git SSH Docker container

My favorite option to backup and version my code and text files is using git with a remote repository. The implementation I have chosen for that consists in running an ssh server, with git, in a Docker container. This has the following advantages over other solutions:

  • 100% reproducible;
  • Limits access to the container in case the account is compromised;
  • Consumes less resources that running a VM.

Dockerfile

The proposed Git SSH Dockerfile is based on the Dockerizing an SSH service example.

FROM ubuntu:14.04

RUN apt-get -y update
RUN apt-get -y install openssh-server
RUN apt-get -y install git

# Setting openssh
RUN mkdir /var/run/sshd
RUN sed -i "s/#PasswordAuthentication yes/PasswordAuthentication no/" /etc/ssh/sshd_config

# Adding git user
RUN adduser --system git
RUN mkdir -p /home/git/.ssh

# Clearing and setting authorized ssh keys
RUN echo '' > /home/git/.ssh/authorized_keys
RUN echo 'First SSH public key' >> /home/git/.ssh/authorized_keys
RUN echo 'Second SSH public key' >> /home/git/.ssh/authorized_keys
# ...

# Updating shell to bash
RUN sed -i s#/home/git:/bin/false#/home/git:/bin/bash# /etc/passwd

EXPOSE 22
CMD ["/usr/sbin/sshd", "-D"]

Running the container

  • Building the image

    $ docker.io build -t git-ssh_img .

  • Running the image

    $ sudo docker.io run -p 1234:22 -d --name git-ssh git-ssh_img

The previous command maps the container's host port 1234 on the container's SSH port. Of course, this port can be changed to any value. One can then ssh to the container with the following command:

$ ssh -p 1234 git@<container_host>