btrfs volumes allows you to share core files between containers and not waste additional disc space. If you use a standard template to make other lxc containers, it makes new containers real cheap as it takes almost no additional disc space for each new one. Yup, I know that Docker uses the same kernel-level isolation mechanisms as LXC. But looks like it is not exactly the same as I've heard of recurrent garbage collection (files) issues with some Docker stuff. I could not guess how a properly designed docker container, with volumes for growing data, could lead to docker image growth. I thought that Docker images were meant to be read-only. BTW, ff your want Docker prebuilt containers, but bare LXC, runc (https://runc.io/) is a kind of Docker over LXC.As far as I could figure, it looks like it basically untars a docker archive in a lxc file tree. But it is still as alpha as one can do. I could not even build the damn stuff. Still, the core concept is really promising.