Since no one has answered you, I'll take a stab. I haven't actually used Docker yet, but I've been lurking extensively. Hopefully someone will correct me if I

Since no one has answered you, I'll take a stab. I haven't actually used Docker yet, but I've been lurking extensively. Hopefully someone will correct me if I get this wrong. A developer will use a Dockerfile to build the main dependencies that you need, and then save an image. Then to deploy code (or other frequently changing data), you pull that base image, add or update whatever else is needed, and save it again. (You can add layers to an image as often as desired.) Then this saved image is pushed into a production environment. It seems like configuration data is often saved in images, so they require zero configuration. However, you can pass as many command line parameters as desired to run the image in production, so you can keep your configuration separated (like http://12factor.net/config http://12factor.net/config) if you want.