SSH server with docker installed in it. Can be used as a "jumper" to e.g. docker exec into another container.
Example:
docker run -d -p 2222:22 -v /var/run/docker.sock:/var/run/docker.sock -v /path/to/dir/with/authorized_keys:/root/.ssh bitrise-docker-ssh:latest
Simple mount a dir with an authorized_keys like:
command="docker exec -it bitrise-main-container bash" ssh-rsa AAA...t
Then, if you SSH into this image (in the above example, ssh into the 2222 port) you'll automatically get docker exec-d into
the other container (in this example the one running with a name bitrise-main-container).