Rancher OS is a Linux distribution where components exist in Docker containers and provides a comprehensive container management platform. It is a distribution you should consider if you are into CoreOS and considering that Docker releases code every two months, why not use a platform based on your chosen container tech?
RancherOS is tiny – the install ISO is ~40MB. They say “…We wanted to run Docker directly on top of the Linux Kernel, and have all user-space Linux services be distributed as Docker containers. By doing this, there would be no need to use a separate software package distribution mechanism for RancherOS itself…” (http://rancher.com/rancher-os/).