I'm not sure how you infer this from what I said? Even Ubuntu have plans to ditch upstart long-term, following Debian's lead to adopt systemd. Nobody is runni

I'm not sure how you infer this from what I said? Even Ubuntu have plans to ditch upstart long-term, following Debian's lead to adopt systemd. Nobody is running "full-blown copies of Ubuntu" under docker, because full-blown would imply "with upstart" and using your distributions' built-in /sbin/init is precluded by the fact that docker overrides it, and also that Upstart doesn't work well in a container. So people are running parts of Ubuntu without understanding that sometimes those parts had expectations of being child processes of upstart, and that upstart would always be running, when in docker-land that's not a reasonable expectation (and OP addresses this by adding in a more reasonable init, which probably handles most of these concerns.) I just built the baseimage-docker, trying to get into it with ssh now, I can't imagine giving anyone a container and not letting them ssh into it, and I've added ssh to containers before in a way that I knew was non-supported or broken, so it's good to have this example. It looks like they are indeed doing it right.