[yebyen]

> Chef, Puppet and Ansible. Those are still necessary for preparing the host machine

In many cases now, they are not. Docker containers can run on CoreOS, which machines are designed to be configured entirely from a cloud-config file, organized in clusters.

With Deis for example, you can build and orchestrate your scalable web service in Docker containers without even writing a Dockerfile, or necessarily knowing anything about how the Docker container is built. The builder creates slugs with the necessary binaries to host your service, and you tell the container how to run itself with a (often one-line) Procfile.

I would still want chef scripts for my database server, but for things that can live in a container on a Fleet cluster, I most certainly do not use Chef, but I absolutely do get reproducible hands-off builds for my runtime environment, and without spending time individually preparing the host machines.