Boot from the CD. The CD contains a basic NixOS installation. (It also contains Memtest86+, useful if you want to test new hardware). When it’s finished booting, it should have detected most of your hardware. The NixOS manual is available on virtual console 8 (press Alt+F8 to access). You get logged in as root (with empty password). If you downloaded the graphical ISO image, you can run start display-manager to start KDE. If you want to continue on the terminal, you can use loadkeys to switch to your preferred keyboard layout. (We even provide neo2 via loadkeys de neo!) The boot process should have brought up networking (check ip a). Networking is necessary for the installer, since it will download lots of stuff (such as source tarballs or Nixpkgs channel binaries). It’s best if you have a DHCP server on your network. Otherwise configure networking manually using ifconfig. To manually configure the network on the graphical installer, first disable network-manager with systemctl stop network-manager. The NixOS installer doesn’t do any partitioning or formatting yet, so you need to do that yourself. Use the following commands: For partitioning: fdisk. For initialising Ext4 partitions: mkfs.ext4. It is recommended that you assign a unique symbolic label to the file system using the option -L label, since this makes the file system configuration independent from device changes. For example: $ mkfs.ext4 -L nixos /dev/sda1 For creating swap partitions: mkswap. Again it’s recommended to assign a label to the swap partition: -L label. For creating LVM volumes, the LVM commands, e.g., $ pvcreate /dev/sda1 /dev/sdb1 $ vgcreate MyVolGroup /dev/sda1 /dev/sdb1 $ lvcreate --size 2G --name bigdisk MyVolGroup $ lvcreate --size 1G --name smalldisk MyVolGroup For creating software RAID devices, use mdadm. Mount the target file system on which NixOS should be installed on /mnt, e.g. $ mount /dev/disk/by-label/nixos /mnt If your machine has a limited amount of memory, you may want to activate swap devices now (swapon device). The installer (or rather, the build actions that it may spawn) may need quite a bit of RAM, depending on your configuration. You now need to create a file /mnt/etc/nixos/configuration.nix that specifies the intended configuration of the system. This is because NixOS has a declarative configuration model: you create or edit a description of the desired configuration of your system, and then NixOS takes care of making it happen. The syntax of the NixOS configuration file is described in , while a list of available configuration options appears in . A minimal example is shown in . The command nixos-generate-config can generate an initial configuration file for you: $ nixos-generate-config --root /mnt You should then edit /mnt/etc/nixos/configuration.nix to suit your needs: $ nano /mnt/etc/nixos/configuration.nix If you’re using the graphical ISO image, other editors may be available (such as vim). If you have network access, you can also install other editors — for instance, you can install Emacs by running nix-env -i emacs. You must set the option boot.loader.grub.device to specify on which disk the GRUB boot loader is to be installed. Without it, NixOS cannot boot. Another critical option is fileSystems, specifying the file systems that need to be mounted by NixOS. However, you typically don’t need to set it yourself, because nixos-generate-config sets it automatically in /mnt/etc/nixos/hardware-configuration.nix from your currently mounted file systems. (The configuration file hardware-configuration.nix is included from configuration.nix and will be overwritten by future invocations of nixos-generate-config; thus, you generally should not modify it.) Depending on your hardware configuration or type of file system, you may need to set the option boot.initrd.kernelModules to include the kernel modules that are necessary for mounting the root file system, otherwise the installed system will not be able to boot. (If this happens, boot from the CD again, mount the target file system on /mnt, fix /mnt/etc/nixos/configuration.nix and rerun nixos-install.) In most cases, nixos-generate-config will figure out the required modules. Examples of real-world NixOS configuration files can be found at . Do the installation: $ nixos-install Cross fingers. If this fails due to a temporary problem (such as a network issue while downloading binaries from the NixOS binary cache), you can just re-run nixos-install. Otherwise, fix your configuration.nix and then re-run nixos-install. As the last step, nixos-install will ask you to set the password for the root user, e.g. setting root password... Enter new UNIX password: *** Retype new UNIX password: *** If everything went well: $ reboot You should now be able to boot into the installed NixOS. The GRUB boot menu shows a list of available configurations (initially just one). Every time you change the NixOS configuration (see Changing Configuration ), a new item is added to the menu. This allows you to easily roll back to a previous configuration if something goes wrong. You should log in and change the root password with passwd. You’ll probably want to create some user accounts as well, which can be done with useradd: $ useradd -c 'Eelco Dolstra' -m eelco $ passwd eelco You may also want to install some software. For instance, $ nix-env -qa \* shows what packages are available, and $ nix-env -i w3m install the w3m browser. To summarise, shows a typical sequence of commands for installing NixOS on an empty hard drive (here /dev/sda). shows a corresponding configuration Nix expression. $ fdisk /dev/sda # (or whatever device you want to install on) $ mkfs.ext4 -L nixos /dev/sda1 $ mkswap -L swap /dev/sda2 $ swapon /dev/sda2 $ mount /dev/disk/by-label/nixos /mnt $ nixos-generate-config --root /mnt $ nano /mnt/etc/nixos/configuration.nix $ nixos-install $ reboot { config, pkgs, ... }: { imports = [ # Include the results of the hardware scan. ./hardware-configuration.nix ]; boot.loader.grub.device = "/dev/sda"; # Note: setting fileSystems is generally not # necessary, since nixos-generate-config figures them out # automatically in hardware-configuration.nix. #fileSystems."/".device = "/dev/disk/by-label/nixos"; # Enable the OpenSSH server. services.sshd.enable = true; }