nixfiles

Some of my .nix files

mostly based on @shazow's work

https://github.com/shazow/nixfiles

Installing

Disk Setup

Rough sketch of the expected disk layout with full-disk encryption.

NOTE: If trying in a VM, make sure to use a SCSI virtual disk (instead of HDA) and UEFI enabled.

# Setup partition layout
# Swap should be >RAM size if you're going to use hibernate
parted /dev/sda -- mklabel gpt
parted /dev/sda -- mkpart ESP fat32 1MiB 512MiB  # boot
parted /dev/sda -- set 1 boot on
parted /dev/sda -- mkpart primary 512MiB -1GiB  # root
parted /dev/sda -- mkpart primary linux-swap -1GiB 100%  # swap

# Generate root private key file
if [[ ! -f cryptroot.key ]]; then
  dd if=/dev/urandom of=cryptroot.key bs=1 count=4096
  chmod 0400 cryptroot.key
fi

# Encrypt the partitions
# Swap partition is also encrypted, so our hibernate state is encrypted.
cryptsetup luksFormat /dev/sda2  # Enter password
cryptsetup luksFormat /dev/sda3  # Enter the same password
cryptsetup luksAddKey /dev/sda2 cryptroot.key
cryptsetup luksAddKey /dev/sda3 cryptroot.key

# Open the encrypted partitions
cryptsetup open -d cryptroot.key /dev/sda2 cryptroot
cryptsetup open -d cryptroot.key /dev/sda3 cryptswap

# Format the underlying partitions
mkfs.fat -F 32 -n efi /dev/sda1
mkswap /dev/mapper/cryptswap
mkfs.btrfs /dev/mapper/cryptroot
mount -o defaults,noatime,compress=lzo,autodefrag /dev/mapper/cryptroot /mnt

# Create volumes on the btrfs root
btrfs subvolume create /mnt/@rootnix
btrfs subvolume create /mnt/@boot
btrfs subvolume create /mnt/@home

# Remount with new volumes
umount /mnt
mount -o compress=lzo,subvol=@rootnix /dev/mapper/cryptroot /mnt
mkdir -p /mnt/boot /mnt/home
mount -o compress=lzo,subvol=@boot /dev/mapper/cryptroot /mnt/boot
mount -o compress=lzo,subvol=@home /dev/mapper/cryptroot /mnt/home
mkdir /mnt/boot/efi
mount /dev/sda1 /mnt/boot/efi

Resume an existing disk setup:

cryptsetup open /dev/sda2 cryptroot  # Enter password
cryptsetup open /dev/sda3 cryptswap  # Enter password

mount -o compress=lzo,subvol=@rootnix /dev/mapper/cryptroot /mnt
mount -o compress=lzo,subvol=@boot /dev/mapper/cryptroot /mnt/boot
mount -o compress=lzo,subvol=@home /dev/mapper/cryptroot /mnt/home
mount /dev/sda1 /mnt/boot/efi

NixOS Setup from another distro

If you're installing from inside another distro, you can use these instructions: https://nixos.org/nixos/manual/index.html#sec-installing-from-other-distro

In Arch, using the aur/nix package does not work.

If we need to add hardware-specific configuration imports, we'll need nixos-hardware (setup instructions). The nix environment activator only includes the nixpkgs channel in the NIX_PATH by default, so we'll need to add that too.

# Activate the nix environment
. $HOME/.nix-profile/etc/profile.d/nix.sh

# Add the nixos-hardware channel
nix-channel --add https://github.com/NixOS/nixos-hardware/archive/master.tar.gz nixos-hardware
nix-channel --update nixos-hardware

# Add the new channel to our NIX_PATH
export NIX_PATH=${NIX_PATH}:${NIX_PATH//nixpkgs/nixos-hardware}

Some other notes for installing from another distro (doesn't apply for a normal install):

• ${disk.efi} should be mounted to /mnt/boot/efi (or whatever the root prefix is).
• ${disk.extraInitrd} should be an absolute path under the root prefix (otherwise when we install outside the root prefix, it messes up the path).

After that, off we go:

sudo PATH="$PATH" NIX_PATH="$NIX_PATH" `which nixos-install` --root /mnt

NixOS Setup from scratch (in a VM)

curl -Ls "https://github.com/shazow/nixfiles/archive/master.zip" -o nixfiles.zip
unzip nixfiles.zip

mkdir /mnt/etc
mv nixfiles-master /mnt/etc/nixos

cd /mnt/etc/nixos
echo \"$(mkpasswd -m sha-512)\" > .hashedPassword.nix
chmod 400 .hashedPassword.nix

# TODO: Make initrd.keys.gz (see Makefile)

cat > disk.nix << EOF
{
  extraInitrd = ./initrd.keys.gz;
  keyFile = "cryptroot.key";
  cryptroot = "/dev/sda2";
  cryptswap = "/dev/sda3";
  efi = "/dev/sda1";
}
EOF

cp hosts/example.nix configuration.nix
echo "Edit configuration.nix ... Some of the paths are wrong here, need to fix."

nixos-install --root /mnt

References

Big thanks to @shazow!

below his friends that helped!

• @arilotter and https://github.com/arilotter/dotfiles
• @attente and https://github.com/attente/dotfiles
• Bonus shoutout to @jpf for checking out NixOS long before it was cool

Full Disk Encryption (FDE)

• https://nixos.wiki/wiki/Full_Disk_Encryption
• https://gist.github.com/ladinu/bfebdd90a5afd45dec811296016b2a3f
• https://gist.github.com/martijnvermaat/76f2e24d0239470dd71050358b4d5134

notes

this config track the unstable channel

nix-channel --add https://nixos.org/channels/nixos-unstable unstable
nix-channel --update unstable