NixOS - Purely Functional Package Management

Transcript

1. Nix(OS) purely functional package management Fueled by

2. f(x)

3. Why is state evil?

4. Expensive to keep track of mutation

5. Which in turns means no rollback

6. Which in turns means no portability

7. The Nix language

8. Why?

9. $ nix-repl > true true > 1 + 1 2

   > (a: a + 1) 1 2

10. We use Nix to describe how to build packages

11. { stdenv, fetchurl, perl }: stdenv.mkDerivation { name = "hello-2.1.1";

    builder = ./builder.sh; src = fetchurl { url = “${packageURL}; md5 = “${md5hash}; }; inherit perl; }

12. Packages are immutable once built

13. Everything lives inside a single directory, the store

14. “Live” packages are symlinked

15. Old packages are still in the store, just not accessible

16. Rollback for free

17. Multiple versions for free

18. Multiple envs for free

19. Puppies for free

20. Ok, maybe not puppies

21. $ nix-repl command not found: nix-repl $ nix-shell -p nix-repl

    [nix-shell:~]$ nix-repl -v nix-repl v1.1.2 [nix-shell:~]$ exit $ nix-repl command not found: nix-repl

22. NixOS is a distribution built around Nix

23. In Nix, to build a package you write a function

24. In NixOS, to build a system you write a function

25. configuration.nix

26. $ fdisk /dev/sda $ mkfs.ext4 -L nixos /dev/sda1 $ mkswap

    -L swap /dev/sda2 $ swapon /dev/sda2 $ mount /dev/disk/by-label/nixos /mnt $ nixos-generate-config --root /mnt $ nano /mnt/etc/nixos/configuration.nix $ nixos-install $ reboot

27. { config, pkgs, ... }: { imports = [ ./hardware-configuration.nix

    ]; boot.loader.grub.device = "/dev/sda"; }

28. Building your system is purely functional

29. Upgrading is the same as rebuilding from scratch

30. No /usr, /sbin/, /share

31. Just /nix/store

32. Nix(OS) cryoptographically hashes all build inputs

33. That means built-in versioning

34. dotfiles, just store ‘em in /nix/store .emacs.d, *wink* *wink* ;)

    ;)

35. More than just a distribution

36. nixops

37. (hail) hydra

38. Questions?