it seems very similar to clearcontainer that was announced a few days ago, i.e. interesting since both are much nicer than "traditional container" solutions.
Now for the interesting stuff.. init process (C): https://github.com/hyperhq/hyperstart
Daemon (Go): https://github.com/hyperhq/hyper/tree/master/hyperdaemon
Stuff to replace with overlayfs ;) https://github.com/hyperhq/hyper/tree/master/storage/aufs