Deis will be released soon. It's an open-source PaaS based on Docker & Chef, with a user experience modeled after Heroku. You create a "formation" which contains a configurable number of backends and Nginx proxies. After you git push your app to the formation, you can scale web=N worker=N just like Heroku. Deis will automatically balance Docker containers across the backends, reconfigure routing, etc.. all using Chef. The goal is to provide a Heroku-like platform where you control everything: Chef Server, PaaS controllers, hosting providers, routing layer, etc..