91 lines
3.3 KiB
XML
91 lines
3.3 KiB
XML
|
<chapter xmlns="http://docbook.org/ns/docbook"
|
|||
|
|
xmlns:xlink="http://www.w3.org/1999/xlink"
|
|||
|
|
version="5.0"
|
|||
|
|
xml:id="sec-upgrading">
|
|||
|
|
|
|||
|
|
<title>Upgrading NixOS</title>
|
|||
|
|
|
|||
|
|
<para>The best way to keep your NixOS installation up to date is to
|
|||
|
|
use one of the NixOS <emphasis>channels</emphasis>. A channel is a
|
|||
|
|
Nix mechanism for distributing Nix expressions and associated
|
|||
|
|
binaries. The NixOS channels are updated automatically from NixOS’s
|
|||
|
|
Git repository after certain tests have passed and all packages have
|
|||
|
|
been built. These channels are:
|
|||
|
|
|
|||
|
|
<itemizedlist>
|
|||
|
|
<listitem>
|
|||
|
|
<para>Stable channels, such as <literal
|
|||
|
|
xlink:href="http://nixos.org/channels/nixos-14.04">nixos-14.04</literal>.
|
|||
|
|
These only get conservative bug fixes and package upgrades. For
|
|||
|
|
instance, a channel update may cause the Linux kernel on your
|
|||
|
|
system to be upgraded from 3.4.66 to 3.4.67 (a minor bug fix), but
|
|||
|
|
not from 3.4.<replaceable>x</replaceable> to
|
|||
|
|
3.11.<replaceable>x</replaceable> (a major change that has the
|
|||
|
|
potential to break things). Stable channels are generally
|
|||
|
|
maintained until the next stable branch is created.</para>
|
|||
|
|
</listitem>
|
|||
|
|
<listitem>
|
|||
|
|
<para>The unstable channel, <literal
|
|||
|
|
xlink:href="http://nixos.org/channels/nixos-unstable">nixos-unstable</literal>.
|
|||
|
|
This corresponds to NixOS’s main development branch, and may thus
|
|||
|
|
see radical changes between channel updates. It’s not recommended
|
|||
|
|
for production systems.</para>
|
|||
|
|
</listitem>
|
|||
|
|
</itemizedlist>
|
|||
|
|
|
|||
|
|
To see what channels are available, go to <link
|
|||
|
|
xlink:href="http://nixos.org/channels"/>. (Note that the URIs of the
|
|||
|
|
various channels redirect to a directory that contains the channel’s
|
|||
|
|
latest version and includes ISO images and VirtualBox
|
|||
|
|
appliances.)</para>
|
|||
|
|
|
|||
|
|
<para>When you first install NixOS, you’re automatically subscribed to
|
|||
|
|
the NixOS channel that corresponds to your installation source. For
|
|||
|
|
instance, if you installed from a 14.04 ISO, you will be subscribed to
|
|||
|
|
the <literal>nixos-14.04</literal> channel. To see which NixOS
|
|||
|
|
channel you’re subscribed to, run the following as root:
|
|||
|
|
|
|||
|
|
<screen>
|
|||
|
|
$ nix-channel --list | grep nixos
|
|||
|
|
nixos https://nixos.org/channels/nixos-unstable
|
|||
|
|
</screen>
|
|||
|
|
|
|||
|
|
To switch to a different NixOS channel, do
|
|||
|
|
|
|||
|
|
<screen>
|
|||
|
|
$ nix-channel --add http://nixos.org/channels/<replaceable>channel-name</replaceable> nixos
|
|||
|
|
</screen>
|
|||
|
|
|
|||
|
|
(Be sure to include the <literal>nixos</literal> parameter at the
|
|||
|
|
end.) For instance, to use the NixOS 14.04 stable channel:
|
|||
|
|
|
|||
|
|
<screen>
|
|||
|
|
$ nix-channel --add http://nixos.org/channels/nixos-14.04 nixos
|
|||
|
|
</screen>
|
|||
|
|
|
|||
|
|
But it you want to live on the bleeding edge:
|
|||
|
|
|
|||
|
|
<screen>
|
|||
|
|
$ nix-channel --add http://nixos.org/channels/nixos-unstable nixos
|
|||
|
|
</screen>
|
|||
|
|
|
|||
|
|
</para>
|
|||
|
|
|
|||
|
|
<para>You can then upgrade NixOS to the latest version in your chosen
|
|||
|
|
channel by running
|
|||
|
|
|
|||
|
|
<screen>
|
|||
|
|
$ nixos-rebuild switch --upgrade
|
|||
|
|
</screen>
|
|||
|
|
|
|||
|
|
which is equivalent to the more verbose <literal>nix-channel --update
|
|||
|
|
nixos; nixos-rebuild switch</literal>.</para>
|
|||
|
|
|
|||
|
|
<warning><para>It is generally safe to switch back and forth between
|
|||
|
|
channels. The only exception is that a newer NixOS may also have a
|
|||
|
|
newer Nix version, which may involve an upgrade of Nix’s database
|
|||
|
|
schema. This cannot be undone easily, so in that case you will not be
|
|||
|
|
able to go back to your original channel.</para></warning>
|
|||
|
|
|
|||
|
|
</chapter>
|