NixOS configuration

Highlights:

• NixOS configurations for desktop, laptop, and server contexts
• Opt-in persistence through impermanence + blank snapshotting on boot
• Encrypted zfs partition
• Deploy secrets using agenix
• Flexible Home Manager config files
• wayland environments (sway)
• Declarative themes
• Github CI/CD and binary cache

Filesystem quirks

On boot the root mount(rpool/local/root) gets wiped to its @blank snapshot. To preserve directories, mount them from either the rpool/safe/data dataset mounted to /data or the rpool/local/cache dataset mounted to /cache.

• /data is for files that we want to persist and backup.
• /cache is for files that we want to persist.

Run src_sh{zfsdiff} tool to discover directories that will be erased on next boot.

References:

• Erase your darlings: immutable infrastructure for mutable systems

First time setup

See ZFS - NixOS Wiki for more information and advanced options for configuring zpool.

1. Create three partitions:
   • Boot
   • Swap
   • ZFS

   disk=/dev/disk/by-id/foo
   sudo parted "$disk" -- mklabel gpt
   sudo parted "$disk" -- mkpart primary 512MiB -8GiB # zfs
   sudo parted "$disk" -- mkpart primary linux-swap -8GiB 100% # swap
   sudo parted "$disk" -- mkpart ESP fat32 1MiB 512MiB # boot
   sudo parted "$disk" -- set 3 esp on
   
   sudo mkswap -L swap "${disk}-part2"
   sudo mkfs.fat -F 32 -n EFI "${disk}-part3"
       

2. Create ZPool:

   zpool create -O mountpoint=none -O encryption=aes-256-gcm -O keyformat=passphrase rpool "${disk}-part1"
       

3. Create datasets and mount them:

   zfs create -o mountpoint=legacy rpool/local
   zfs create -o mountpoint=legacy rpool/safe
   
   zfs create -o mountpoint=legacy rpool/local/root
   zfs snapshot rpool/local/root@blank
   zfs create -o mountpoint=legacy rpool/local/nix
   zfs set compression=lz4 rpool/local/nix
   zfs create -o mountpoint=legacy rpool/local/nix-store
   zfs set compression=lz4 rpool/local/nix-store
   zfs create -o mountpoint=legacy rpool/local/cache
   zfs set compression=lz4 rpool/local/cache
   zfs create -o mountpoint=legacy rpool/safe/data
   zfs set compression=lz4 rpool/safe/data
   
   mount -t zfs rpool/local/root /mnt
   
   mkdir -p /mnt/boot
   mount "${disk}-part3" /mnt/boot
   
   mkdir -p /mnt/nix/store
   mount -t zfs rpool/local/nix /mnt/nix
   mount -t zfs rpool/local/nix-store /mnt/nix/store
   
   mkdir -p /mnt/cache
   mount -t zfs rpool/local/cache /mnt/cache
   
   mkdir -p /mnt/data
   mount -t zfs rpool/safe/data /mnt/data
       

4. Set src_nix{networking.hostId} to src_sh{cat /etc/machine-id | head -c 8}