This tutorial describes how to install NixOS on a single disk system using
disko. You will also need to refer to the NixOS manual, which is available
here.
Please note that disko will reformat the entire disk and overwrite any
existing partitions. Dual booting with other operating systems is not supported.
Configurations for the most common disk layouts are provided in the
examples directory
of the disko repository. Decide which of these layouts best suits your
requirements. If you're not sure which layout to pick, use the
hybrid
configuration. This layout is compatible with both BIOS and EFI systems.
Refer to the reference manual for more information about the sample layouts and how to build your own configuration.
Once you've chosen your layout, you'll need to make a note of the URL to the raw file. To do this, open the file in Github. Immediately below the list of contributors, you will see a button labelled 'RAW' near the right hand side. Click this. The URL of the raw file will appear in the search bar of your browser. It will look something like this:
https://raw.githubusercontent.com/nix-community/disko/master/example/hybrid.nix
Download the NixOS ISO image from the NixOS download page, and create a bootable USB drive following the instructions in Section 2.4.1 "Booting from a USB flash drive" of the NixOS manual. Boot the machine from this USB drive.
Identify the name of your system disk by using the lsblk command as follows:
$ lsblk
The output from this command will look something like this:
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
nvme0n1 259:0 0 1,8T 0 disk
In this example, an empty NVME SSD with 2TB space is shown with the disk name "nvme0n1". Make a note of the disk name as you will need it later.
In Step 1, you chose a disk layout configuration from the examples directory, and made a note of its URL.
Your configuration needs to be saved on the new machine
as /tmp/disko-config.nix. You can do this using the curl command to download
from the url you noted above, using the -o option to save the file as
disko-config.nix. Your commands would look like this if you had chosen the
hybrid layout:
cd /tmp
$ curl https://raw.githubusercontent.com/nix-community/disko/master/example/hybrid.nix -o disko-config.nix
The following step will partition and format your disk, and mount it to /mnt.
Replace <disk-name> with the name of your disk obtained in Step 1.
Please note: This will erase any existing data on your disk.
$ sudo nix run github:nix-community/disko -- --mode disko /tmp/disko-config.nix --arg disks '[ "/dev/<disk-name>" ]'
For example, if the disk name is nvme0n1, the command would be:
$ sudo nix run github:nix-community/disko -- --mode disko /tmp/disko-config.nix --arg disks '[ "/dev/nvme0n1" ]'
After the command has run, your file system should have been formatted and mounted. You can verify this by running the following command:
$ mount | grep /mnt
The output should look like this if your disk name is nvme0n1.
/dev/nvme0n1p1 on /mnt type ext4 (rw,relatime,stripe=2)
/dev/nvme0n1p2 on /mnt/boot type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)
Your disks have now been formatted and mounted, and you are ready to complete
the NixOS installation as described in the
NixOS manual -
see the section headed "Installing", Steps 3 onwards. However, you will need
to include the partitioning and formatting configurations that you copied into
/tmp/disko-config.nix in your configuration, rather than allowing NixOS to
generate information about your file systems. When you are configuring the
system as per Step 4 of the manual, you should:
a) Include the no-filesystems switch when using the nixos-generate-config
command to generate an initial configuration.nix. You will be supplying the
file system configuration details from disko-config.nix. Your CLI command to
generate the configuration will be:
$ nixos-generate-config --no-filesystems --root /mnt
This will create the file configuration.nix in /mnt/etc/nixos.
b) Move the disko configuration to /etc/nixos
$ mv /tmp/disko-config.nix /mnt/etc/nixos
c) You can now edit configuration.nix as per your requirements. This is
described in Step 4 of the manual. For more information about configuring your
system, refer to the NixOS manual.
Chapter 6, Configuration Syntax
describes the NixOS configuration syntax, and
Appendix A, Configuration Options
gives a list of available options. You can find also find a minimal example of a
NixOS configuration in the manual:
Example: NixOS Configuration.
d) When editing configuration.nix, you will need to add the disko NixOS
module and disko-config.nix to the imports section. This section will already
include the file ./hardware-configuration.nix, and you can add the new entries
just below this. This section will now include:
imports =
[ # Include the results of the hardware scan.
./hardware-configuration.nix
"${builtins.fetchTarball "https://github.com/nix-community/disko/archive/master.tar.gz"}/module.nix"
];
disko.devices = pkgs.callPackage ./disko-config.nix {
disks = [ "/dev/<disk-name>" ]; # replace this with your disk name i.e. /dev/nvme0n1
};
e) If you chose the hybrid-partition scheme, then choose grub as a bootloader,
otherwise follow the recommendations in Step 4 of the Installation section
of the NixOS manual. The following configuration for grub works for both EFI
and BIOS systems. Add this to your configuration.nix, commenting out the
existing lines that configure systemd-boot. The entries will look like this:
# ...
#boot.loader.systemd-boot.enable = true;
#boot.loader.efi.canTouchEfiVariables = true;
# replace this with your disk i.e. /dev/nvme0n1
boot.loader.grub.devices = [ "/dev/<disk-name>" ];
boot.loader.grub.enable = true;
boot.loader.grub.efiSupport = true;
boot.loader.grub.efiInstallAsRemovable = true;
# ...
f) Finish the installation and reboot your machine,
$ nixos-install
$ reboot