nixpkgs/nixos/doc/manual/installation/installing.xml

<chapter xmlns="http://docbook.org/ns/docbook"
            xmlns:xlink="http://www.w3.org/1999/xlink"
            xmlns:xi="http://www.w3.org/2001/XInclude"
            version="5.0"
            xml:id="sec-installation">
 <title>Installing NixOS</title>
 <section xml:id="sec-installation-booting">
  <title>Booting the system</title>

  <para>
   NixOS can be installed on BIOS or UEFI systems. The procedure for a UEFI installation is by and large the same as a BIOS installation. The differences are mentioned in the steps that follow.
  </para>

  <para>
   The installation media can be burned to a CD, or now more commonly, "burned" to a USB drive (see <xref linkend="sec-booting-from-usb"/>).
  </para>

  <para>
   The installation media contains a basic NixOS installation. When it’s finished booting, it should have detected most of your hardware.
  </para>

  <para>
   The NixOS manual is available on virtual console 8 (press Alt+F8 to access) or by running <command>nixos-help</command>.
  </para>

  <para>
   You are logged-in automatically as <literal>nixos</literal>. The <literal>nixos</literal> user account has an empty password so you can use <command>sudo</command> without a password.
  </para>

  <para>
   If you downloaded the graphical ISO image, you can run <command>systemctl start display-manager</command> to start the desktop environment. If you want to continue on the terminal, you can use <command>loadkeys</command> to switch to your preferred keyboard layout. (We even provide neo2 via <command>loadkeys de neo</command>!)
  </para>

  <section xml:id="sec-installation-booting-networking">
   <title>Networking in the installer</title>

   <para>
    The boot process should have brought up networking (check <command>ip a</command>). 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 <command>ifconfig</command>.
   </para>

   <para>
    To manually configure the network on the graphical installer, first disable network-manager with <command>systemctl stop NetworkManager</command>.
   </para>

   <para>
    To manually configure the wifi on the minimal installer, run <command>wpa_supplicant -B -i interface -c &lt;(wpa_passphrase 'SSID' 'key')</command>.
   </para>

   <para>
    If you would like to continue the installation from a different machine you need to activate the SSH daemon via <command>systemctl start sshd</command>. You then must set a password for either <literal>root</literal> or <literal>nixos</literal> with <command>passwd></command> to be able to login.
   </para>
  </section>
 </section>
 <section xml:id="sec-installation-partitioning">
  <title>Partitioning and formatting</title>

  <para>
   The NixOS installer doesn’t do any partitioning or formatting, so you need to do that yourself.
  </para>

  <para>
   The NixOS installer ships with multiple partitioning tools. The examples below use <command>parted</command>, but also provides <command>fdisk</command>, <command>gdisk</command>, <command>cfdisk</command>, and <command>cgdisk</command>.
  </para>

  <para>
   The recommended partition scheme differs depending if the computer uses <emphasis>Legacy Boot</emphasis> or <emphasis>UEFI</emphasis>.
  </para>

  <section xml:id="sec-installation-partitioning-UEFI">
   <title>UEFI (GPT)</title>

   <para>
    Here's an example partition scheme for UEFI, using <filename>/dev/sda</filename> as the device.
    <note>
     <para>
      You can safely ignore <command>parted</command>'s informational message about needing to update /etc/fstab.
     </para>
    </note>
   </para>

   <para>
    <orderedlist>
     <listitem>
      <para>
       Create a <emphasis>GPT</emphasis> partition table.
<screen language="commands"><prompt># </prompt>parted /dev/sda -- mklabel gpt</screen>
      </para>
     </listitem>
     <listitem>
      <para>
       Add the <emphasis>root</emphasis> partition. This will fill the disk except for the end part, where the swap will live, and the space left in front (512MiB) which will be used by the boot partition.
<screen language="commands"><prompt># </prompt>parted /dev/sda -- mkpart primary 512MiB -8GiB</screen>
      </para>
     </listitem>
     <listitem>
      <para>
       Next, add a <emphasis>swap</emphasis> partition. The size required will vary according to needs, here a 8GiB one is created.
<screen language="commands"><prompt># </prompt>parted /dev/sda -- mkpart primary linux-swap -8GiB 100%</screen>
       <note>
        <para>
         The swap partition size rules are no different than for other Linux distributions.
        </para>
       </note>
      </para>
     </listitem>
     <listitem>
      <para>
       Finally, the <emphasis>boot</emphasis> partition. NixOS by default uses the ESP (EFI system partition) as its <emphasis>/boot</emphasis> partition. It uses the initially reserved 512MiB at the start of the disk.
<screen language="commands"><prompt># </prompt>parted /dev/sda -- mkpart ESP fat32 1MiB 512MiB
<prompt># </prompt>parted /dev/sda -- set 3 boot on</screen>
      </para>
     </listitem>
    </orderedlist>
   </para>

   <para>
    Once complete, you can follow with <xref linkend="sec-installation-partitioning-formatting"/>.
   </para>
  </section>

  <section xml:id="sec-installation-partitioning-MBR">
   <title>Legacy Boot (MBR)</title>

   <para>
    Here's an example partition scheme for Legacy Boot, using <filename>/dev/sda</filename> as the device.
    <note>
     <para>
      You can safely ignore <command>parted</command>'s informational message about needing to update /etc/fstab.
     </para>
    </note>
   </para>

   <para>
    <orderedlist>
     <listitem>
      <para>
       Create a <emphasis>MBR</emphasis> partition table.
<screen language="commands"><prompt># </prompt>parted /dev/sda -- mklabel msdos</screen>
      </para>
     </listitem>
     <listitem>
      <para>
       Add the <emphasis>root</emphasis> partition. This will fill the the disk except for the end part, where the swap will live.
<screen language="commands"><prompt># </prompt>parted /dev/sda -- mkpart primary 1MiB -8GiB</screen>
      </para>
     </listitem>
     <listitem>
      <para>
       Finally, add a <emphasis>swap</emphasis> partition. The size required will vary according to needs, here a 8GiB one is created.
<screen language="commands"><prompt># </prompt>parted /dev/sda -- mkpart primary linux-swap -8GiB 100%</screen>
       <note>
        <para>
         The swap partition size rules are no different than for other Linux distributions.
        </para>
       </note>
      </para>
     </listitem>
    </orderedlist>
   </para>

   <para>
    Once complete, you can follow with <xref linkend="sec-installation-partitioning-formatting"/>.
   </para>
  </section>

  <section xml:id="sec-installation-partitioning-formatting">
   <title>Formatting</title>

   <para>
    Use the following commands:
    <itemizedlist>
     <listitem>
      <para>
       For initialising Ext4 partitions: <command>mkfs.ext4</command>. It is recommended that you assign a unique symbolic label to the file system using the option <option>-L <replaceable>label</replaceable></option>, since this makes the file system configuration independent from device changes. For example:
<screen>
<prompt># </prompt>mkfs.ext4 -L nixos /dev/sda1</screen>
      </para>
     </listitem>
     <listitem>
      <para>
       For creating swap partitions: <command>mkswap</command>. Again it’s recommended to assign a label to the swap partition: <option>-L <replaceable>label</replaceable></option>. For example:
<screen>
<prompt># </prompt>mkswap -L swap /dev/sda2</screen>
      </para>
     </listitem>
     <listitem>
      <variablelist>
       <varlistentry>
        <term>
         UEFI systems
        </term>
        <listitem>
         <para>
          For creating boot partitions: <command>mkfs.fat</command>. Again it’s recommended to assign a label to the boot partition: <option>-n <replaceable>label</replaceable></option>. For example:
<screen>
<prompt># </prompt>mkfs.fat -F 32 -n boot /dev/sda3</screen>
         </para>
        </listitem>
       </varlistentry>
      </variablelist>
     </listitem>
     <listitem>
      <para>
       For creating LVM volumes, the LVM commands, e.g., <command>pvcreate</command>, <command>vgcreate</command>, and <command>lvcreate</command>.
      </para>
     </listitem>
     <listitem>
      <para>
       For creating software RAID devices, use <command>mdadm</command>.
      </para>
     </listitem>
    </itemizedlist>
   </para>
  </section>
 </section>
 <section xml:id="sec-installation-installing">
  <title>Installing</title>

  <orderedlist>
   <listitem>
    <para>
     Mount the target file system on which NixOS should be installed on <filename>/mnt</filename>, e.g.
<screen>
<prompt># </prompt>mount /dev/disk/by-label/nixos /mnt
</screen>
    </para>
   </listitem>
   <listitem>
    <variablelist>
     <varlistentry>
      <term>
       UEFI systems
      </term>
      <listitem>
       <para>
        Mount the boot file system on <filename>/mnt/boot</filename>, e.g.
<screen>
<prompt># </prompt>mkdir -p /mnt/boot
<prompt># </prompt>mount /dev/disk/by-label/boot /mnt/boot
</screen>
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
   </listitem>
   <listitem>
    <para>
     If your machine has a limited amount of memory, you may want to activate swap devices now (<command>swapon <replaceable>device</replaceable></command>). The installer (or rather, the build actions that it may spawn) may need quite a bit of RAM, depending on your configuration.
<screen>
<prompt># </prompt>swapon /dev/sda2</screen>
    </para>
   </listitem>
   <listitem>
    <para>
     You now need to create a file <filename>/mnt/etc/nixos/configuration.nix</filename> that specifies the intended configuration of the system. This is because NixOS has a <emphasis>declarative</emphasis> 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 <xref linkend="sec-configuration-syntax"/>, while a list of available configuration options appears in <xref
    linkend="ch-options"/>. A minimal example is shown in <xref
    linkend="ex-config"/>.
    </para>
    <para>
     The command <command>nixos-generate-config</command> can generate an initial configuration file for you:
<screen>
<prompt># </prompt>nixos-generate-config --root /mnt</screen>
     You should then edit <filename>/mnt/etc/nixos/configuration.nix</filename> to suit your needs:
<screen>
<prompt># </prompt>nano /mnt/etc/nixos/configuration.nix
</screen>
     If you’re using the graphical ISO image, other editors may be available (such as <command>vim</command>). If you have network access, you can also install other editors — for instance, you can install Emacs by running <literal>nix-env -f '&lt;nixpkgs&gt;' -iA emacs</literal>.
    </para>
    <variablelist>
     <varlistentry>
      <term>
       BIOS systems
      </term>
      <listitem>
       <para>
        You <emphasis>must</emphasis> set the option <xref linkend="opt-boot.loader.grub.device"/> to specify on which disk the GRUB boot loader is to be installed. Without it, NixOS cannot boot.
       </para>
      </listitem>
     </varlistentry>
     <varlistentry>
      <term>
       UEFI systems
      </term>
      <listitem>
       <para>
        You <emphasis>must</emphasis> set the option <xref linkend="opt-boot.loader.systemd-boot.enable"/> to <literal>true</literal>. <command>nixos-generate-config</command> should do this automatically for new configurations when booted in UEFI mode.
       </para>
       <para>
        You may want to look at the options starting with <option><link linkend="opt-boot.loader.efi.canTouchEfiVariables">boot.loader.efi</link></option> and <option><link linkend="opt-boot.loader.systemd-boot.enable">boot.loader.systemd</link></option> as well.
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
    <para>
     If there are other operating systems running on the machine before installing NixOS, the <xref linkend="opt-boot.loader.grub.useOSProber"/> option can be set to <literal>true</literal> to automatically add them to the grub menu.
    </para>
    <para>
     If you need to configure networking for your machine the configuration options are described in <xref linkend="sec-networking"/>.
    </para>
    <para>
     Another critical option is <option>fileSystems</option>, specifying the file systems that need to be mounted by NixOS. However, you typically don’t need to set it yourself, because <command>nixos-generate-config</command> sets it automatically in <filename>/mnt/etc/nixos/hardware-configuration.nix</filename> from your currently mounted file systems. (The configuration file <filename>hardware-configuration.nix</filename> is included from <filename>configuration.nix</filename> and will be overwritten by future invocations of <command>nixos-generate-config</command>; thus, you generally should not modify it.) Additionally, you may want to look at <link xlink:href="https://github.com/NixOS/nixos-hardware">Hardware configuration for known-hardware</link> at this point or after installation.
    </para>
    <note>
     <para>
      Depending on your hardware configuration or type of file system, you may need to set the option <option>boot.initrd.kernelModules</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 installation media again, mount the target file system on <filename>/mnt</filename>, fix <filename>/mnt/etc/nixos/configuration.nix</filename> and rerun <filename>nixos-install</filename>.) In most cases, <command>nixos-generate-config</command> will figure out the required modules.
     </para>
    </note>
   </listitem>
   <listitem>
    <para>
     Do the installation:
<screen>
<prompt># </prompt>nixos-install</screen>
     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 <command>nixos-install</command>. Otherwise, fix your <filename>configuration.nix</filename> and then re-run <command>nixos-install</command>.
    </para>
    <para>
     As the last step, <command>nixos-install</command> will ask you to set the password for the <literal>root</literal> user, e.g.
<screen>
setting root password...
Enter new UNIX password: ***
Retype new UNIX password: ***</screen>
     <note>
      <para>
       For unattended installations, it is possible to use <command>nixos-install --no-root-passwd</command> in order to disable the password prompt entirely.
      </para>
     </note>
    </para>
   </listitem>
   <listitem>
    <para>
     If everything went well:
<screen>
<prompt># </prompt>reboot</screen>
    </para>
   </listitem>
   <listitem>
    <para>
     You should now be able to boot into the installed NixOS. The GRUB boot menu shows a list of <emphasis>available configurations</emphasis> (initially just one). Every time you change the NixOS configuration (see <link
        linkend="sec-changing-config">Changing Configuration</link> ), a new item is added to the menu. This allows you to easily roll back to a previous configuration if something goes wrong.
    </para>
    <para>
     You should log in and change the <literal>root</literal> password with <command>passwd</command>.
    </para>
    <para>
     You’ll probably want to create some user accounts as well, which can be done with <command>useradd</command>:
<screen>
<prompt>$ </prompt>useradd -c 'Eelco Dolstra' -m eelco
<prompt>$ </prompt>passwd eelco</screen>
    </para>
    <para>
     You may also want to install some software. For instance,
<screen>
<prompt>$ </prompt>nix-env -qaP \*</screen>
     shows what packages are available, and
<screen>
<prompt>$ </prompt>nix-env -f '&lt;nixpkgs&gt;' -iA w3m</screen>
     install the <literal>w3m</literal> browser.
    </para>
   </listitem>
  </orderedlist>
 </section>
 <section xml:id="sec-installation-summary">
  <title>Installation summary</title>

  <para>
   To summarise, <xref linkend="ex-install-sequence" /> shows a typical sequence of commands for installing NixOS on an empty hard drive (here <filename>/dev/sda</filename>). <xref linkend="ex-config"
/> shows a corresponding configuration Nix expression.
  </para>

  <example xml:id="ex-partition-scheme-MBR">
   <title>Example partition schemes for NixOS on <filename>/dev/sda</filename> (MBR)</title>
<screen language="commands">
<prompt># </prompt>parted /dev/sda -- mklabel msdos
<prompt># </prompt>parted /dev/sda -- mkpart primary 1MiB -8GiB
<prompt># </prompt>parted /dev/sda -- mkpart primary linux-swap -8GiB 100%</screen>
  </example>

  <example xml:id="ex-partition-scheme-UEFI">
   <title>Example partition schemes for NixOS on <filename>/dev/sda</filename> (UEFI)</title>
<screen language="commands">
<prompt># </prompt>parted /dev/sda -- mklabel gpt
<prompt># </prompt>parted /dev/sda -- mkpart primary 512MiB -8GiB
<prompt># </prompt>parted /dev/sda -- mkpart primary linux-swap -8GiB 100%
<prompt># </prompt>parted /dev/sda -- mkpart ESP fat32 1MiB 512MiB
<prompt># </prompt>parted /dev/sda -- set 3 boot on</screen>
  </example>

  <example xml:id="ex-install-sequence">
   <title>Commands for Installing NixOS on <filename>/dev/sda</filename></title>
   <para>
    With a partitioned disk.
<screen language="commands">
<prompt># </prompt>mkfs.ext4 -L nixos /dev/sda1
<prompt># </prompt>mkswap -L swap /dev/sda2
<prompt># </prompt>swapon /dev/sda2
<prompt># </prompt>mkfs.fat -F 32 -n boot /dev/sda3        # <lineannotation>(for UEFI systems only)</lineannotation>
<prompt># </prompt>mount /dev/disk/by-label/nixos /mnt
<prompt># </prompt>mkdir -p /mnt/boot                      # <lineannotation>(for UEFI systems only)</lineannotation>
<prompt># </prompt>mount /dev/disk/by-label/boot /mnt/boot # <lineannotation>(for UEFI systems only)</lineannotation>
<prompt># </prompt>nixos-generate-config --root /mnt
<prompt># </prompt>nano /mnt/etc/nixos/configuration.nix
<prompt># </prompt>nixos-install
<prompt># </prompt>reboot</screen>
   </para>
  </example>

  <example xml:id='ex-config'>
   <title>NixOS Configuration</title>
<programlisting>
{ config, pkgs, ... }: {
  imports = [
    # Include the results of the hardware scan.
    ./hardware-configuration.nix
  ];

  <xref linkend="opt-boot.loader.grub.device"/> = "/dev/sda";   # <lineannotation>(for BIOS systems only)</lineannotation>
  <xref linkend="opt-boot.loader.systemd-boot.enable"/> = true; # <lineannotation>(for UEFI systems only)</lineannotation>

  # Note: setting fileSystems is generally not
  # necessary, since nixos-generate-config figures them out
  # automatically in hardware-configuration.nix.
  #<link linkend="opt-fileSystems._name__.device">fileSystems."/".device</link> = "/dev/disk/by-label/nixos";

  # Enable the OpenSSH server.
  services.sshd.enable = true;
}
</programlisting>
  </example>
 </section>
 <section xml:id="sec-installation-additional-notes">
  <title>Additional installation notes</title>

  <xi:include href="installing-usb.xml" />

  <xi:include href="installing-pxe.xml" />

  <xi:include href="installing-virtualbox-guest.xml" />

  <xi:include href="installing-from-other-distro.xml" />

  <xi:include href="installing-behind-a-proxy.xml" />
 </section>
</chapter>