Re: GRUB fallback mechanism [was Re: Brain storming cool Guix features]

[Ricardo Wurmus <rekado@elephly.net>]

swedebugia <swedebugia@riseup.net> writes:

> Leo Famulari <leo@famulari.name> skrev: (11 januari 2019 23:32:12 CET)
>>On Mon, Jan 07, 2019 at 05:48:39PM +0100, L p R n d n wrote:
>>> - Currently, I think the only way for a GuixSD installation to break
>>is
>>>   if something goes wrong with the bootloader. Might be nice to have
>>a
>>>   tool (in the install image I suppose) to recover the bootloader.
>>>   Maybe 'guix system init' can deal with that king of cases for now,
>>I
>>>   don't know, but a dedicated command might be able to use the
>>original
>>>   store, restore previous generations etc.
>>
>>Apparently GRUB has a feature that records a "fallback" system to boot
>>if booting fails.
>>
>>Maybe when reconfiguring, Guix could set the current system as the
>>fallback so that it would always boot.
>>
>>If we did that, we'd want to warn the user somehow... not sure how to
>>achieve that.
>>
>>Discussion of this feature at NixOS:
>>
>>https://github.com/NixOS/nixpkgs/issues/26332
>
> I don't think automatic fallback is a good idea because it unnecessarily complicates a now well working simple part of the OS.
> KISS is a nice principle.

I think exposing this GRUB feature would be good, even if not enabled by
default.  It does not seem very complicated and can be very useful for
some users.

Unfortunately, it doesn’t help us when GRUB itself is broken with an
upgrade, which I think is what was suggested earlier.

--
Ricardo