diff --git a/doc/manual/troubleshooting.xml b/doc/manual/troubleshooting.xml index 2961f8e1233..b78c35a35e1 100644 --- a/doc/manual/troubleshooting.xml +++ b/doc/manual/troubleshooting.xml @@ -81,4 +81,50 @@ just exit from the rescue shell. +
+ +Rolling back configuration changes + +After running nixos-rebuild to switch to a +new configuration, you may find that the new configuration doesn’t +work very well. In that case, there are several ways to return to a +previous configuration. + +First, the GRUB boot manager allows you to boot into any +previous configuration that hasn’t 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: + + +$ /run/current-system/bin/switch-to-configuration boot + + + +Second, you can switch to the previous configuration in a running +system: + + +$ nixos-rebuild switch --rollback + +This is equivalent to running: + + +$ /nix/var/nix/profiles/system-N-link/bin/switch-to-configuration switch + +where N is the number of the NixOS system +configuration. To get a list of the available configurations, do: + + +$ ls -l /nix/var/nix/profiles/system-*-link +... +lrwxrwxrwx 1 root root 78 Aug 12 13:54 /nix/var/nix/profiles/system-268-link -> /nix/store/202b...-nixos-13.07pre4932_5a676e4-4be1055 + + + + +
+ +