Installing NixOSBoot 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 and brought up networking (check
ifconfig). 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.The NixOS manual is available on virtual console 8
(press Alt+F8 to access).Login as root and the empty
password.If you downloaded the graphical ISO image, you can
run start display-manager to start KDE.The NixOS installer doesn’t do any partitioning or
formatting yet, so you need to 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
, since this
makes the file system configuration independent from device
changes. For example:
$ mkfs.ext4 -L nixos /dev/sda1For creating swap partitions:
mkswap. Again it’s recommended to assign a
label to the swap partition: .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 MyVolGroupFor 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
The vim text editor is also available.You must set the option
to specify on which disk
the GRUB boot loader is to be installed. Without it, NixOS cannot
boot.Another critical option is ,
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
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:
$ rebootYou 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 (seeChanging
Configuration ), a new item appears in the menu. This allows you to
easily roll back to another 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 eelcoYou 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.Commands for Installing NixOS on <filename>/dev/sda</filename>
$ 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
$ rebootNixOS Configuration
{ 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;
}