Interesting, thanks. Personally, Docker is already too monolithic, and this just looks like it adds unnecessary coupling to something should be less coupled in the first place. I'd prefer to use etcd.

I think rkt is making some good decisions and is worth keeping an eye on. Not sure I love the tight coupling to systemd, but the fact that it avoids the PID 0 problem and lets containers be their own processes (separate from the "engine", which can choreograph containers through the systemd API, building on all of its process handling logic) are improvements over Docker. In fact, rkt uses the same networking model as Kubernetes.