Stable Docker OS with small footprint.
Easy to install an setup with cloud-config.yml by manual editing or with config tools.
You can choose your preferred distro for installing an setting up the system.
If you are planning to run your applications in docker, you will quickly realize that you will want as little OS as possible on the systems where you will run docker. RancherOS takes this to a new level by having all of the system services run as docker containers in what is referred to as a system-docker. The install is small and simple.