peterwaller got it right, but let me try and give a little more color. Deis is provides a private Heroku-like platform powered by Docker & Chef.
Once Deis is up and running, developers deploy with `git push deis master` and they automatically get a configurable number of Docker "runtime" containers spread across multiple VM hosts, a set of Nginx proxies that route traffic to the Docker containers, resulting in a fully functional distributed application.
How does this work? With Deis the ops folks initialize a "formation" that includes multiple VMs/instances for a) hosting Docker containers and b) proxying traffic into those containers. When a developer creates a new application, pushes a new build, sets an environment variable, etc.. Deis automatically builds the Docker image, distributes it, executes it and reconfigures Nginx proxies to route traffic to it. Chef is used to store platform state and orchestrate changes across the formation.
Once Deis is up and running, developers deploy with `git push deis master` and they automatically get a configurable number of Docker "runtime" containers spread across multiple VM hosts, a set of Nginx proxies that route traffic to the Docker containers, resulting in a fully functional distributed application.
How does this work? With Deis the ops folks initialize a "formation" that includes multiple VMs/instances for a) hosting Docker containers and b) proxying traffic into those containers. When a developer creates a new application, pushes a new build, sets an environment variable, etc.. Deis automatically builds the Docker image, distributes it, executes it and reconfigures Nginx proxies to route traffic to it. Chef is used to store platform state and orchestrate changes across the formation.