48 lines
		
	
	
		
			1.6 KiB
		
	
	
	
		
			XML
		
	
	
	
	
	
		
		
			
		
	
	
			48 lines
		
	
	
		
			1.6 KiB
		
	
	
	
		
			XML
		
	
	
	
	
	
| 
								 | 
							
								<section 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-rollback">
							 | 
						|||
| 
								 | 
							
								
							 | 
						|||
| 
								 | 
							
								<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 doesn’t
							 | 
						|||
| 
								 | 
							
								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 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:
							 | 
						|||
| 
								 | 
							
								
							 | 
						|||
| 
								 | 
							
								<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>
							 |