Rancher vs. Centurion vs. dockersh

Rancher is an open source container management platform that includes full distributions of Kubernetes, Apache Mesos and Docker Swarm, and makes it simple to operate container clusters on any cloud or infrastructure platform.

A deployment tool for Docker, made by New Relic. Takes containers from a Docker registry and runs them on a fleet of hosts with the correct environment variables, host volume mappings, and port mappings. Supports rolling deployments out of the box, and makes it easy to ship applications to Docker servers. New Relic is using it to run their production infrastructure.

dockersh is designed to be used as a login shell on machines with multiple interactive users. When a user invokes dockersh, it will bring up a Docker container (if not already running), and then spawn a new interactive shell in the container's namespace.