https://www.youtube.com/watch?v=D2IvmJORD2s&feature=youtu.be

I find it a little alarming to see systemd-nspawn creating subvolumes without warning which can be annoying since they can be difficult to delete manually. Why does it need a subvolume on /var/lib/machines ? IIUC that's only needed if the container is going to host ANOTHER container which is a little bizarre, no?