GNU Guix

For immutable, repeatable machines we’re trialing GNU Guix in preference to NixOS. Both build whole systems and packages from declarative, functional definitions. Guix uses Guile Scheme throughout, puts a strong emphasis on reproducible builds and a full-source bootstrap, and guix time-machine pins an entire environment to an exact revision. It’s a trial because its ecosystem is smaller than Nix’s, and hardware that needs non-free firmware requires additional channels.