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/).
Rancher supplies the entire software stack needed to manage containers in production and works well with all the usual suspects (Kubernetes, Mesos, Swarm). The Rancher solution provides orchestration, scheduling, app catalog and authentication – take a look here for detail (http://docs.rancher.com/rancher/latest/en/).
Rancher has pedigree; the team behind Rancher includes co-founder and CEO Sheng Liang, who was was CTO of the Cloud Platforms group at Citrix Systems after their acquisition of Cloud.com, where he was co-founder and CEO.