To set up a NixOS system, you usually boot into a live NixOS system and install it onto a local disk as outlined in the manual. You can then modify the system configuration to tailor it to your needs. The build system Hydra builds live images like ISO images, container tarballs or AMIs based on their definition in nixpkgs. These images are made available for download on the official website.
In the past year some Mayflower colleagues have started using and contributing to NixOS, a purely functional GNU/Linux distribution that combines package and configuration management. We decided that we would give it a try in production but stumbled upon some issues that had to be resolved first. We have added new packages, services and fixed up some internal. Due to this work two colleagues have even gained commit access in the process.
I have been following the development of NixOps for some months. NixOps is a cloud deployment tool using nix, the functional package manager for unix systems. Nix makes it very intuitive to define absolute package dependencies. No more thinking and guessing about required runtime dependencies. NixOps supports deploying to different platforms. Bare-metal, cloud, and even virtual environments like virtualbox work out of the box. I have worked in many projects using vagrant.