My idea was to build small docker container which will be acting as Linux jumpbox. This project is based on already exiting one https://github.com/warden/docker-jumpbox but it has been rewritten and size of image has been reduced.

Additionally, I wanted to have possibility to have many ssh jumpbox containers on Docker host (or Swarm for redundancy) where each of them will only have access to particular network subnet. This is quite useful in large network environment when we have many teams using one (two) jump hosts to access their separated environments. This has been achieved by filtering access to network segments using iptables rules on each Docker host.

To build docker image clone this repo and run build command. You can add additional packages by editing Dockerfile.

$ cd ssh-docker-jumpbox $ docker build -t ssh-jumpbox . 

Listing images:

$ docker images REPOSITORY TAG IMAGE ID CREATED SIZE ssh-jumpbox latest ff4a2f8bdd50 3 days ago 91.9MB 

This is just general guidance and you don't need to follow it step-by-step. You can user your own build image or use mine from Docker Hub.

Each user is authenticated by ssh key during login, and to be able to do it, specially 'crafted' file is required. It's like normal authorized_keys file but with username at the beginning. General file format is:

username:ssh_public_key 

Created file need to be placed in the config directory

config/authorized_keys 

Just use the docker-compose file