Bug#597084: grub-pc: /etc/kernel/postinst.d/zz-update-grub fails inside openvz chroot

[Vladimir 'φ-coder/phcoder' Serbinenko]

On 11/08/2010 06:15 PM, Michael Prokop wrote:
> * Vladimir 'φ-coder/phcoder' Serbinenko <phcoder at gmail.com> [Mon Nov 08, 2010 at 05:33:41PM +0100]:
>
>   
>>> It fails because of the way openvz guests look like (simfs as
>>> rootfs):
>>>       
>   
>> What does linux expect as root= on command line in such config? How such
>> config can be detected and needed parameters figured out? Would it be
>> possible to have a root ssh access to such a system (since it's virtual
>> I guess you could copy one that contains no private data and wipe it
>> after we're done).
>>     
> There's no root=... in the kernel command line involved, openvz
> guests are like chroots.
>   
If I understand this statement correctly you mean that GRUB isn't used
to boot the system and grub.cfg isn't used, right? Then  update-grub
shouldn't be run at all. Perhaps you shouldn't even install GRUB
packages in this case.
(actually this information shifts the issue from my area [upstream] to
Debian-specific). Can someone familiar with packaging handle it?
> There's a simple way to trigger the problem on your own:
>
>   mount -o remount,rw,exec,dev,suid /dev/shm
>   debootstrap sid /dev/shm/testchroot http://cdn.debian.net/debian
>   mount --bind /dev /dev/shm/testchroot/dev
>   chroot /dev/shm/testchroot /bin/bash
>   apt-get install grub-pc
>   grub-probe --target=device /
>
> -> this will return:
>
>   grub-probe: error: cannot find a device for / (is /dev mounted?).
>
> as well - the same problem as with the openvz guest.
> Building on tmpfs like on /dev/shm is actually not uncommon if speed
> matters for a buildprocess.
>
> Maybe testing for /dev/root and skipping update-grub/grub-probe
> calls if the device doesn't exist is enough to resolve this issue?
>
> regards,
> -mika-
>   


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko


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