NixOS - Purely Functional Package Management

Transcript

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

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2. f(x)
   

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3. Why is state evil?
   

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4. Expensive to keep
   track of mutation
   

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5. Which in turns
   means no rollback
   

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6. Which in turns
   means no portability
   

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7. The Nix language
   

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8. Why?
   

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9. $ nix-repl
   > true
   true
   > 1 + 1
   2
   > (a: a + 1) 1
   2
   

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10. We use Nix to describe
    how to build packages
    

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11. { stdenv, fetchurl, perl }:
    stdenv.mkDerivation {
    name = "hello-2.1.1";
    builder = ./builder.sh;
    src = fetchurl {
    url = “${packageURL};
    md5 = “${md5hash};
    };
    inherit perl;
    }
    

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12. Packages are immutable
    once built
    

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13. Everything lives inside a
    single directory, the store
    

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14. “Live” packages are
    symlinked
    

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

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16. Rollback for free
    

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17. Multiple versions for free
    

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18. Multiple envs for free
    

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19. Puppies for free
    

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20. Ok, maybe not puppies
    

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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
    

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22. NixOS is a distribution
    built around Nix
    

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

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

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25. configuration.nix
    

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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
    

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27. { config, pkgs, ... }:
    {
    imports =
    [
    ./hardware-configuration.nix
    ];
    boot.loader.grub.device = "/dev/sda";
    }
    

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28. Building your system is
    purely functional
    

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29. Upgrading is the same as
    rebuilding from scratch
    

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

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31. Just /nix/store
    

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32. Nix(OS)
    cryoptographically
    hashes all build inputs
    

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33. That means
    built-in versioning
    

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

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35. More than just a
    distribution
    

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36. nixops
    

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37. (hail) hydra
    

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38. Questions?
    

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