I've often been thinking about container systems like Rocket. Of course there is Docker. Docker is growing so fast that it has been hard to keep up with its development.
Rocket is very young and now is a good time to start following along. I've read through the specs and code. I really like the minimalism (which is largely due to its infancy.)
I am a fan of the ACI format, but less so of systemd. I'll just get over it.