Another alternative, for what it's worth: https://github.com/rciorba/pidunu https://github.com/rciorba/pidunu I've created an Ubuntu PPA packaging of it (https

Another alternative, for what it's worth: https://github.com/rciorba/pidunu https://github.com/rciorba/pidunu I've created an Ubuntu PPA packaging of it (https://launchpad.net/~danieldent/+archive/ubuntu/pidunu https://launchpad.net/~danieldent/+archive/ubuntu/pidunu) and you can see an example of it in use at: https://github.com/DanielDent/docker-powerdns https://github.com/DanielDent/docker-powerdns For situations involving multiple processes, there's also https://github.com/just-containers/s6-overlay https://github.com/just-containers/s6-overlay Example use: https://github.com/DanielDent/docker-nginx-ssl-proxy https://github.com/DanielDent/docker-nginx-ssl-proxy (automated Let's Encrypt SSL front-end)