change to /etc/default/grub causes prompt on grub-pc upgrade

[Scott Moser]

Binary package hint: grub2

In the build of the UEC images, I modify /etc/default/grub so that the grub menu is shown on first boot (rather than hidden).

On a grub-pc upgrade, the user is then forced to merge the diffs of that file. The changes are made at [1].
The diff is basically:

 │ -#GRUB_HIDDEN_TIMEOUT_QUIET=true
 │ +GRUB_HIDDEN_TIMEOUT_QUIET=true
..
 │ -GRUB_TERMINAL=console
 │ +#GRUB_TERMINAL=console

--
[1] http://bazaar.launchpad.net/%7Eubuntu-on-ec2/vmbuilder/automated-ec2-builds/annotate/head%3A/vmbuilder-uec-ec2-fixes

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: grub-pc 1.99~rc1-3ubuntu3 [modified: usr/sbin/grub-set-default]
ProcVersionSignature: User Name 2.6.38-5.32-virtual 2.6.38-rc6
Uname: Linux 2.6.38-5-virtual i686
Architecture: i386
Date: Tue Mar 8 13:42:04 2011
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: grub2
UpgradeStatus: No upgrade log present (probably fresh install)

[Scott Moser (smoser)]

How can I make those changes in the build process so the user wont' be prompted on upgrade?

[Colin Watson (cjwatson)]

Set GRUB_HIDDEN_TIMEOUT_QUIET=false rather than commenting it out, and that part will get simpler.

I don't know if you can do anything about GRUB_TERMINAL=console. Fundamentally, the configuration file has been changed both locally (as far as ucf is concerned) and in the package.

[Scott Moser (smoser)]

Both settings are needed due to the desire to run the image in kvm.

I need GRUB_HIDDEN_TIMEOUT_QUIET=false because kvm does not pass the shift key by itself through to the guest. Without it, then, the user is not able to change the entry (other than they can fail once, and reboot thanks to recordfail).

I need GRUB_GFXMODE=console because I want to be able to boot in 'kvm -curses', where there is no graphical console. Without that change, grub changes to '800 x 599 Graphic mode' (as reported by kvm in curses mode).

[Scott Moser (smoser)]

note about above, I just tested the GRUB_GFXMODE on lucid's kvm (natty could potentially be different). I have verified that shift does not pass through in the natty cycle but did not do that just now.

[Scott Moser (smoser)]

So, without making the above two changes, the images are much less usable under kvm. If I make the changes then automated upgrade is broken.

It is not as bad as I had originally thought, though has the 'cloud-config' apt-upgrade runs like:
  apt-get --option Dpkg::Options::=--force-confold --assume-yes upgrade

So it doesn't block completely.

[Phillip Susi (psusi)]

Closing since this was a question rather than a bug report.