Nix

My grand, declarative, and unified application, service, environment, and machine configuration, secret, and package management in a single flake. ❤️ ❄️

NOTE: Everything in here is highly specific to my personal preference. I can't recommend you actually use this in any way, but hopefully some stuff in here is useful inspiration.

Quick Start

You don't have even have to clone this crap yourself. How cool is that!

But if you're gonna change stuff you had better setup the pre-commit hook:

ln -s $PWD/pre-commit.bash .git/hooks/pre-commit

NixOS

nixos-rebuild switch --flake git+https://git.lyte.dev/lytedev/nix

Not NixOS

$ curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | sh -s -- install
$ nix profile install github:nix-community/home-manager
$ home-manager switch --flake git+https://git.lyte.dev/lytedev/nix

Advanced Usage

Push NixOS Config

host=your_host
nix run nixpkgs#nixos-rebuild -- --flake "git+https://git.lyte.dev/lytedev/nix#$host" \
  --target-host "root@$host" --build-host "root@$host" \
  switch --show-trace

Safer Method

# initialize a delayed reboot by a process you can kill later if things look good
# note that the amount of time you give it probably needs to be enough time to both complete the upgrade
# _and_ perform whatever testing you need
host=your_host
ssh -t "root@$host" "bash -c '
  set -m
  (sleep 300; reboot;) &
  jobs -p
  bg
  disown
'"

# build the system and start running it, but do NOT set the machine up to boot to that system yet
# we will test things and make sure it works first
# if it fails, the reboot we started previously will automatically kick in once the timeout is reached
# and the machine will boot to the now-previous iteration
nix run nixpkgs#nixos-rebuild -- --flake "git+https://git.lyte.dev/lytedev/nix#$host" \
  --target-host "root@$host" --build-host "root@$host" \
  test --show-trace

# however you like, verify the system is running as expected
# if it is, run the same command with "switch" instead of "test"
# otherwise, we will wait until the machine reboots back into the 
# this is crude, but should be pretty foolproof
# the main gotcha is that the system is already unbootable or non-workable, but
# if you always use this method, that should be an impossible state to get into

# if we still have ssh access and the machine fails testing, just rollback
# instead of waiting for the reboot
# TODO: this is not tested yet
ssh "root@$host" nixos-rebuild --rollback switch

Provisioning New NixOS Hosts

# establish network access
# plug in ethernet or do the wpa_cli song and dance for wifi
wpa_cli scan
wpa_cli scan_results
wpa_cli add_network 0
wpa_cli set_network 0 ssid "MY_SSID"
wpa_cli set_network 0 psk "MY_WIFI_PASSWORD"
wpa_cli enable_network 0
wpa_cli save_config

# disk encryption key (if needed)
echo -n "password" > /tmp/secret.key

# partition disks
nix-shell --packages git --run "sudo nix run \
  --extra-experimental-features nix-command \
  --extra-experimental-features flakes \
  github:nix-community/disko -- \
    --flake 'git+https://git.lyte.dev/lytedev/nix#${PARTITION_SCHEME}' \
    --mode disko \
    --arg disks '[ \"/dev/${DISK}\" ]'"

# install
nix-shell --packages git \
  --run "sudo nixos-install \
    --flake 'git+https://git.lyte.dev/lytedev/nix#${FLAKE_ATTR}' \
    --option substituters 'https://cache.nixos.org https://nix.h.lyte.dev' \
    --option trusted-public-keys 'cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= h.lyte.dev:HeVWtne31ZG8iMf+c15VY3/Mky/4ufXlfTpT8+4Xbs0='"

To Do

• I don't understand Nix well enough to know why stuff is being compiled even when I have a binary cache
  • Maybe it detects different CPUs and will recompile certain packages for per-CPU optimizations?
    • How does this factor in with "pureness"?