Machine Management

These notes are still a work-in-progress and are currently largely for my personal use only.

Home-Manager Example

Install Nix standalone:

curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | sh -s -- install

Set proper Nix settings in /etc/nix/nix.conf:

substituters = https://cache.nixos.org/ https://github-public.cachix.org
trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= github-public.cachix.org-1:xofQDaQZRkCqt+4FMyXS5D6RNenGcWwnpAXRXJ2Y5kc=
narinfo-cache-positive-ttl = 0
narinfo-cache-negative-ttl = 0
experimental-features = nix-command flakes auto-allocate-uids

Add these Nix channels via nix-channel --add URL NAME:

$ nix-channel --list
home-manager https://github.com/nix-community/home-manager/archive/release-24.05.tar.gz
nixpkgs https://nixos.org/channels/nixos-24.05

Install home-manager: https://nix-community.github.io/home-manager/index.xhtml#sec-install-standalone

Example home.nix file for personal use:

{ config, pkgs, lib, ... }:
let
  user = "andrew";
  homedir = "/home/${user}";
  anixsrc = ./path/to/sources/anixpkgs/.;
in with import ../dependencies.nix; {
  home.username = user;
  home.homeDirectory = homedir;
  programs.home-manager.enable = true;

  imports = [
    "${anixsrc}/pkgs/nixos/components/opts.nix"
    "${anixsrc}/pkgs/nixos/components/base-pkgs.nix"
    "${anixsrc}/pkgs/nixos/components/base-dev-pkgs.nix"
    "${anixsrc}/pkgs/nixos/components/x86-rec-pkgs.nix"
    "${anixsrc}/pkgs/nixos/components/x86-graphical-pkgs.nix"
    "${anixsrc}/pkgs/nixos/components/x86-graphical-dev-pkgs.nix"
    "${anixsrc}/pkgs/nixos/components/x86-graphical-rec-pkgs.nix"
  ];

  mods.opts.standalone = true;
  mods.opts.homeDir = homedir;
  mods.opts.homeState = "23.05";
  mods.opts.browserExec = "google-chrome-stable";
}

*-rec-* packages can be removed for non-recreational use.

Symlink to ~/.config/home-manager/home.nix.

Corresponding ~/.bashrc:

export NIX_PATH=$HOME/.nix-defexpr/channels:/nix/var/nix/profiles/per-user/root/channels${NIX_PATH:+:$NIX_PATH}
. "$HOME/.nix-profile/etc/profile.d/hm-session-vars.sh"
export NIXPKGS_ALLOW_UNFREE=1
# alias code='codium'
# eval "$(direnv hook bash)"

Build and Deploy a Raspberry Pi NixOS SD Configuration

Since the hardware configuration for the Raspberry Pi is well understood, it makes sense to skip the installer step and deploy a fully-fledged clusure instead.

nixos-generate -f sd-aarch64 --system aarch64-linux -c /path/to/anixpkgs/pkgs/nixos/configurations/config.nix [-I nixpkgs=/path/to/alternative/nixpkgs]

nix-shell -p zstd --run "unzstd -d /nix/store/path/to/image.img.zst"

sudo dd if=/path/to/image.img of=/dev/sdX bs=4096 conv=fsync status=progress

On the Pi, connect to the internet, copy over SSH keys (maybe no need for /root/.ssh/) and then set up the Nix channel(s):

sudo nix-channel --add https://nixos.org/channels/nixos-[NIXOS-VERSION] nixos
sudo nix-channel --update

Note that the nixos-generate step may not have "aarch-ified" the anixpkgs packages (that's something for me to look into) so the anix-upgrade setup steps are especially important:

Make a ~/sources directory
Symlink the configuration file even if it doesn't exist yet
Run anix-upgrade to aarch-ify everything

Build a Raspberry Pi NixOS SD Installer Image

nixos-generate -f sd-aarch64-installer --system aarch64-linux -c /path/to/rpi/config.nix [-I nixpkgs=/path/to/alternative/nixpkgs]

nix-shell -p zstd --run "unzstd -d /nix/store/path/to/image.img.zst"

sudo dd if=/path/to/image.img of=/dev/sdX bs=4096 conv=fsync status=progress

On the Pi, copy over SSH keys (including to /root/.ssh/!) and then set up the Nix channel:

sudo nix-channel --add https://nixos.org/channels/nixos-[NIXOS-VERSION] nixos
sudo nix-channel --update

Installation Instructions on a New Machine

Sources

https://nixos.wiki/wiki/NixOS_Installation_Guide
https://alexherbo2.github.io/wiki/nixos/install-guide/

Note: You can replace steps 1-8 with a kexec kernel load and disk formatting with disko:

Download a NixOS ISO image.
Plug in a USB stick large enough to accommodate the image.
Find the right device with lsblk or fdisk -l. Replace /dev/sdX with the proper device (do not use /dev/sdX1 or partitions of the disk; use the whole disk /dev/sdX).
Burn ISO to USB stick with

cp nixos-xxx.iso /dev/sdX
# OR
dd if=nixos.iso of=/dev/sdX bs=4M status=progress conv=fdatasync

On the new machine, one-time boot UEFI into the USB stick on the computer (will need to disable Secure Boot from BIOS first)
Wipe the file system:

wipefs [--all -a] /dev/sda

gparted
1. Create a GUID table: Device > Create Partition Table > GPT
  1. Select /dev/sda
  2. Entire disk
2. Create the boot partition: Partition > New
  1. Free space preceding (MiB): 1
  2. New size (MiB): 512
  3. Free space following (MiB): Rest
  4. Align to: MiB
  5. Create as: Primary Partition
  6. Partition name: EFI
  7. File system: fat32
  8. Label: EFI
3. Add the boot flag
  1. Right-click on /dev/sda1 to manage flags
  2. Add the boot flag and enable esp (should be automatic with GPT)
4. Create the root partition: Partition > New
  1. Free space preceding (MiB): 0
  2. New size (MiB): Rest
  3. Free space following (MiB): 0
  4. Align to: MiB
  5. Create as: Primary Partition
  6. Partition name: NixOS
  7. File system: ext4
  8. Label: NixOS
5. Apply modifications
Mount root and boot partitions:

mkdir /mnt/nixos
mount /dev/disk/by-label/NixOS /mnt/nixos
mkdir /mnt/nixos/boot
mount /dev/disk/by-label/EFI /mnt/nixos/boot

Generate an initial configuration (you'll want it to enable WiFi connectivity and a web browser at least):

nixos-generate-config --root /mnt/nixos
# /etc/nixos/configuration.nix
# /etc/nixos/hardware-configuration.nix

Do the installation:

nixos-install --root /mnt/nixos

If everything went well:

reboot

Log into Github and generate an SSH key for authentication.
Clone and link an editable version of the configuration:

mkdir -p /data/andrew/sources # or in an alternate location, for now
git clone git@github.com:goromal/anixpkgs.git /data/andrew/sources/anixpkgs
cat /etc/nixos/hardware-configuration.nix > /data/andrew/sources/anixpkgs/pkgs/nixos/hardware/[hardware-configuration.nix] # update link/headings in configuration.nix
sudo mv /etc/nixos/configuration.nix /etc/nixos/old.configuration.nix
sudo mv /etc/nixos/hardware-configuration.nix /etc/nixos/old.hardware-configuration.nix
sudo ln -s /data/andrew/sources/anixpkgs/pkgs/nixos/configurations/[your-configuration.nix] /etc/nixos/configuration.nix

Make other needed updates to the configuration, then apply:

sudo nixos-rebuild boot
sudo reboot

Upgrading NixOS versions with `anixpkgs`

Aside from the source code changes in anixpkgs, ensure that your channels have been updated for the root user:

# e.g., upgrading to 24.05:
home-manager https://github.com/nix-community/home-manager/archive/release-24.05.tar.gz
nixos https://nixos.org/channels/nixos-24.05
nixpkgs https://nixos.org/channels/nixos-24.05

sudo nix-channel --update. Then upgrade with

anix-upgrade [source specification] --local --boot

Cloud Syncing

The following mount points are recommended (using rclone to set up):

dropbox:secrets -> rclone copy -> ~/secrets
dropbox:configs-> rclone copy -> ~/configs
dropbox:Games -> rclone copy -> ~/games
box:data -> rclone copy -> ~/data
box:.devrc -> rclone copy -> ~/.devrc
drive:Documents -> rclone copy -> ~/Documents

Build a NixOS ISO Image

TODO (untested); work out hardware configuration portion.

nixos-generate -f iso -c /path/to/personal/configuration.nix [-I nixpkgs=/path/to/alternative/nixpkgs]

sudo dd if=/path/to/nixos.iso of=/dev/sdX bs=4M conv=fsync status=progress