Manual: Add section on how to do rollbacks

This commit is contained in:
Eelco Dolstra 2013-08-20 13:30:59 +02:00
parent f2480af162
commit f4c42695cb

View File

@ -81,4 +81,50 @@ just exit from the rescue shell.</para>
</section>
<section>
<title>Rolling back configuration changes</title>
<para>After running <command>nixos-rebuild</command> to switch to a
new configuration, you may find that the new configuration doesnt
work very well. In that case, there are several ways to return to a
previous configuration.</para>
<para>First, the GRUB boot manager allows you to boot into any
previous configuration that hasnt been garbage-collected. These
configurations can be found under the GRUB submenu “NixOS - All
configurations”. This is especially useful if the new configuration
fails to boot. After the system has booted, you can make the selected
configuration the default for subsequent boots:
<screen>
$ /run/current-system/bin/switch-to-configuration boot</screen>
</para>
<para>Second, you can switch to the previous configuration in a running
system:
<screen>
$ nixos-rebuild switch --rollback</screen>
This is equivalent to running:
<screen>
$ /nix/var/nix/profiles/system-<replaceable>N</replaceable>-link/bin/switch-to-configuration switch</screen>
where <replaceable>N</replaceable> is the number of the NixOS system
configuration. To get a list of the available configurations, do:
<screen>
$ ls -l /nix/var/nix/profiles/system-*-link
<replaceable>...</replaceable>
lrwxrwxrwx 1 root root 78 Aug 12 13:54 /nix/var/nix/profiles/system-268-link -> /nix/store/202b...-nixos-13.07pre4932_5a676e4-4be1055
</screen>
</para>
</section>
</chapter>