# 0x29a nixos config

My personal nixos configuration files for different environments.

## basic system installation

- The installations presented in this repository are always luks encrypted
- For simplicity I'm using device labels rather than uuids

1. the partitioning layout should look somewhat like this after the installation

```bash
NAME               MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINTS
nvme0n1            259:0    0 476.9G  0 disk
├─nvme0n1p1        259:1    0     2G  0 part  /boot
└─nvme0n1p2        259:2    0 474.9G  0 part
  └─cryptroot      254:0    0 474.9G  0 crypt
    ├─lvmroot-swap 254:1    0    20G  0 lvm   [SWAP]
    ├─lvmroot-home 254:2    0   250G  0 lvm   /home
    └─lvmroot-root 254:3    0 204.9G  0 lvm   /nix/store
``` 

2. prepare the installation

```bash
# format the boot partition
mkfs.fat -F 32 /dev/sda1 -n "nixboot"
# create an encrypted partition
cryptsetup luksFormat -y --label="nixcrypt" /dev/sda2
# open the encrypted partition and map it to /dev/mapper/cryptroot
cryptsetup luksOpen /dev/sda2 cryptroot

# create the physical volume
pvcreate /dev/mapper/cryptroot
# create a volume group inside
vgcreate lvmroot /dev/mapper/cryptroot
# create the swap volume
lvcreate --size 8G lvmroot --name nwap
# if you desire, create a home volume
lvcreate --size 150G lvmroot --name home
# create the root volume
lvcreate -l 100%FREE lvmroot --name root

# format as usual for root partition
mkfs.ext4 -L "nixroot" /dev/mapper/lvmroot-root
# if you previously made the home partition, do it too
mkfs.ext4 -L "nixhome" /dev/mapper/lvmroot-home
# format the swap partition
mkswap -L "nixswap" /dev/mapper/lvmroot-swap

# mount root
mount /dev/disk/by-label/nixroot /mnt
# mount boot
mount --mkdir /dev/sda1 /mnt/boot
# again, if you did the home volume
mount --mkdir /dev/disk/by-label/nixhome /mnt/home
# turn on swap
swapon /dev/disk/by-label/nixswap
```

3. prepare nixos


```bash
# generate templates and update the hardware-configuration.nix
sudo nixos-generate-config --root /mnt

# add cryptd to the kernelModules
boot.initrd.kernelModules = [ "dm-snapshot" "cryptd" ];

# add file systems using labels
fileSystems."/" =
  { device = "/dev/disk/by-label/nixroot";
    fsType = "ext4";
  };
fileSystems."/boot" =
  { device = "/dev/disk/by-label/nixboot";
    fsType = "vfat";
    options = [ "fmask=0022" "dmask=0022" ];
  };
fileSystems."/home" =
  { device = "/dev/disk/by-label/nixhome";
    fsType = "ext4";
  };
swapDevices =
  [ { device = "/dev/disk/by-label/nixswap"; }
  ];

# point the bootloader to the luks device
boot.initrd.luks.devices."cryptroot".device = "/dev/disk/by-label/nixcrypt";
```

4. install nixos

```bash
cd /mnt
sudo nixos-install
```

## how to deploy the inital config

- Don't forget to install the bootloader, if you changed it since `nixos-install`

```bash
$ sudo nixos-rebuild --install-bootloader switch --flake .#host_name
```

## how to upgrade the system

```bash
$ cd /path/to/repo
$ sudo nix flake update
$ sudo nixos-rebuild switch --flake .#host_name
$ sudo nix-collect-garbage
```

## how to use nix-helper

The tool nix-helper is installed by this configuration. It simplifies administrating nixos and adds more output to the rebuild command. It also features a diff after a successful build. The command uses the `NH_FLAKE` environment variable to be able to run from whatever directory.

Basic commands with a set `NH_FLAKE` variable are:

```bash
$ nh os switch
$ nh os build
$ nh os test
$ nh clean all --keep 5
```

There is also the option to interface with home-manager by using `nh home switch`but this isn't necessary since home-manager is imported as a module in this config.

## author

aaron <aaron@0x29a.ch>