Readings:
https://blog.phusion.nl/2015/01/20/docker-and-the-pid-1-zombie-reaping-problem/
https://engineeringblog.yelp.com/2016/01/dumb-init-an-init-for-docker.html
P.S. Docker now has natively supported the init mechanism:
https://docs.docker.com/engine/reference/run/#specify-an-init-process
