Re: execution of update-grub in chroots might fail

[Felix Zielcke]

Am Donnerstag, den 24.12.2009, 22:28 +0100 schrieb Robert Millan:
> On Mon, Dec 14, 2009 at 11:56:21AM +0000, Colin Watson wrote:
> > The simplest fix is to add '&& [ -e /boot/grub/grub.cfg ]' to the
> test
> > in memtest86+;
> 
> Uhm should we make this check part of update-grub?  Or even part of
> grub-mkconfig?

I don't think grub-mkconfig should check for that. And if it does then
we should make it optional by adding something like --update as option
to it.
If people of other distributions compile GRUB 2 they should be able to
just use grub-mkconfig directly to create their initial config without
much hassle.

> > that is, if the configuration file hasn't been generated
> > already, it shouldn't be updated. (This check is in the memtest86+
> > postinst in Ubuntu.) This accounts for the OpenVZ problem as well as
> for
> > other reasons why GRUB might not actually be being used as a boot
> > loader.
> > 
> > You're right that it is suboptimal that every package has to
> implement
> > the check itself. My instinct is that the semantics of update-grub
> ought
> > to change slightly, so that it really is an *update* - that is, it
> > shouldn't by default generate a configuration file if there isn't
> one
> > already. It could have a --force option (or better name?) for
> > convenience, for use by the grub2 packaging itself, and for use by
> the
> > installer. Anything much more complex than that smells of
> > overengineering to me.
> > 
> > Note, though, that care would need to be taken to ensure that
> > grub-installer is changed in step; it's important to minimise the
> > chances of consequential installer brokenness. There's little
> urgency on
> > this so we could afford the time for a proper transition. For
> example,
> > update-grub could accept but ignore the new option for a while;
> then,
> > after the relevant version of grub2 has moved to testing,
> grub-installer
> > could be updated to use it; then, at some later point, the default
> > semantics of update-grub could change.
> > 
> > If that's too complicated, we could just add an --if-exists option
> or
> > something that does what memtest86+ and other similar packages need.
> > There are very few packages in this boat, so it may not be worth
> very
> > much effort to deal with them.
> > 
> > Robert, Felix, what do you think?
> 
> I think it's fine to make this update conditional.  My only concern is
> that
> external packages have a mechanism to add their stuff into grub.cfg
> (this
> was one of the key motivations for initial grub-mkconfig design).
> 

In Debian at least they probable all rely that grub-pc etc. is installed
first.
If you have grub2 installed but no config then you probable don't want
that e.g. memtest86+ suddenly creates it.
-- 
Felix Zielcke
Proud Debian Maintainer and GNU GRUB developer