• Preamble
• Impermanent Filesystem
• Installation
  • Requirements
  • Partitioning
  • Encryption
  • Formatting
  • Filesystem Mounting
  • UUID/PARTUUID Configuration
  • Passwords
  • Build
• Tasks
  • Priority
  • Documentation
  • Aesthetic
  • Backlog

I am revisiting NixOS after two/three long years full of macOS and Arch Linux (primarily the former unfortunately). This is my second major attempt with NixOS and it seems to be going much better (due to better hardware compatibility with different hardware). I am running this nix flake on a Framework 13 with a AMD 7040 series processor; my configuration choice thus reflect this. I will try to make the config as modular and usable to those without this laptop; let me know if there are any issues.

I have chosen to implement impermanence into my configuration. This is done the more “advanced” way as decribed https://github.com/nix-community/impermanence. There are two partitions for my SSD: boot and root. The boot partition is the standard EFI setup using fat32. The root partition is a btrfs setup that mounts / to a subvolume root. On each reboot, the root subvolume is copied to a new timestamped subvolume (as a backup) and wiped. These backups are permanently deleted after 30 days from creation. I like this approach because if my system were to shutdown unexpectedly I have a convenient way to recover non-persisting files.

My reasoning for impermanence is to have complete control over the literal state of my system. In a traditonal personal computer, there comes a time where refreshing the computer is a must; there is simply too much conflicting state that has been saved over many months (or years!) which cause problems. Impermanence solves this problem by never having a large footprint other than important documents and state which I care to keep. For example, I do not keep ~~/.mozilla~ or ~~/Downloads~ on reboot. The former is because browsers collect so much state and refreshing it is just good practice. The latter is to force myself to give new files a purpose, otherwise they are unimportant and non-persistent.

Currently, it is required to locally clone this repository and change at least the hardware/disk configuration.

From either the minimal/graphical NixOS iso, run the following as root while replacing <hard-drive> and <usb> as needed.

parted /dev/<hard-drive> -- mklabel gpt
parted /dev/<hard-drive> -- mkpart primary 0% 100% # Reserve the entire hard drive for storage (not boot). 

parted /dev/<usb> -- mklabel gpt
parted /dev/<usb> -- mkpart ESP 1MB 512MB            # boot partition
parted /dev/<usb> -- mkpart primary1 512MB 544MB     # where the luks header will reside
parted /dev/<usb> -- mkpart primary2 544MB 100%      # rest of the usb for storage. format as desired
parted /dev/<usb> -- set 1 esp on

The partition scheme should be setup now. To encrypt the hard-drive and extract the header to the usb drive, run:

cryptsetup luksFormat /dev/<hard-drive>1 --type luks2 --header /dev/<usb>2 # answer prompts and provide password
cryptsetup luksOpen /dev/<hard-drive>1 crypted --header /dev/<usb>2 # open hard drive as /dev/mapper/crypted

Now we can format the necessary partitions.

mkfs.fat -F 32 -n boot /dev/<usb>1
mkfs.btrfs /dev/mapper/crypted

Now we can create our btrfs subvolumes.

mkdir -p /tmp/drive
mount /dev/mapper/crypted -o compress-force=zstd,noatime,ssd /tmp/drive
cd /tmp/drive

btrfs subvolume create nix
btrfs subvolume create root
btrfs subvolume create backups
btrfs subvolume create persist

Now we mount these subvolumes as such:

mount /dev/mapper/crypted -o compress-force=zstd,noatime,ssd,subvol=root /mnt

mkdir /mnt/{nix,persist,etc,etc/nixos,boot}

mount /dev/mapper/crypted -o compress-force=zstd,noatime,ssd,subvol=nix /mnt/nix
mount /dev/mapper/crypted -o compress-force=zstd,noatime,ssd,subvol=persist /mnt/persist

mount /dev/<usb>1 /mnt/boot

We do NOT need to run nixos-generate-config --root /mnt. We will use the config provided by this repo/flake by editing the UUIDS for each block device. This sounds scary but I have added module options to simplify this process. This is a bit goofy, but I believe this is slightly “simpler” than generating a new hardware configuration and manually changing everything to appear like the flake system hardware configuration.

nix-shell -p git # only if git is not present. The live iso has git pre-installed.
cd /mnt/persist
git clone https://github.com/mjalen/dot # this is read-only for https, you will not be able to push 

cd /mnt/persist/dot
lsblk --output NAME,UUID,PARTUUID

In the hardware file /mnt/persist/dot/systems/valhalla/default.nix, update the PARTUUIDs and UUIDs.

# line 8 ...
valhalla.hardware = {
    enabled = true;
    encryptedPARTUUID = "..."; # /dev/<hard-drive>1 -> PARTUUID 
    headerPARTUUID = "..."; # /dev/<usb>2 -> PARTUUID
    bootUUID = "..."; # /dev/<usb>1 -> UUID
    unencryptedUUID = "..."; # /dev/mapper/crypted -> UUID
};
# ...

The last thing that is needed are user passwords, so we don’t have to redefine them on each reboot.

mkdir -p /mnt/persist/psk
cd /mnt/persist/psk
mkpasswd > root
mkpasswd > jalen # only change the name if you edited the user configuration

From the flake directory /mnt/persist/dot (or where-ever you cloned this repo) run

nixos-install --impure --flake .#valhalla 

This command should take a while because the operating system is installing. The command will ask to define a root password at the end; We declared one in a file and through the flake, so it really doesn’t matter what you enter here. To complete setup, it is safer to run umount /mnt/boot before reboot.

• [X] Add install instructions to README.md. (Depends on root `default.nix`)
• [ ] Over-all file organization and make it consistent.
• [ ] Reduce RAM consumption. My current screenie has nearly 8GB of RAM usage! I am not running that much right?
  • Note: I do believe nix does use more RAM than typical OSes, but I doubt by this much!

• [ ] Add luks header backup guide.
• [ ] Add usb recovery guide using the luks header backup to access the encrypted btrfs block device and recreated the usb boot drive.

• [ ] Write scripts to display a notification when the brightness or volume are changed.
• [ ] Window shadows.

• [ ] Get screen sharing + Zoom working.
• [ ] Get HDMI working.