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

[Witold Baryluk]

Package: grub2-common
Version: 2.06-2
Followup-For: Bug #597084
X-Debbugs-Cc: witold.baryluk at gmail.com

This problem shows also in very similar form in live-boot environment:

Setting up linux-image-5.17.0-3-amd64 (5.17.11-1) ...
/etc/kernel/postinst.d/dkms:
dkms: running auto installation service for kernel 5.17.0-3-amd64:Deprecated feature: REMAKE_INITRD
Deprecated feature: REMAKE_INITRD
.
/etc/kernel/postinst.d/initramfs-tools:
I: update-initramfs is disabled (live system is running on read-only media).
/etc/kernel/postinst.d/zz-update-grub:
/usr/sbin/grub-probe: error: failed to get canonical path of `overlay'.
run-parts: /etc/kernel/postinst.d/zz-update-grub exited with return code 1
dpkg: error processing package linux-image-5.17.0-3-amd64 (--configure):
 installed linux-image-5.17.0-3-amd64 package post-installation script subprocess returned error exit status 1


While the grub obviously is not used in the live-boot environment itself,
due to construction of live-boot, it must be installed there. Then if the
users tries to perform an upgrade of packages inside the live
environment, it might trigger update of the kernel packages too, which
will fail at update-grub as presented above.

Would be nice to detect this chroot and live-boot enviornments, and skip update-grub.

Even on live-boot environment, /boot/grub/grub.cfg does exist, and while
modifying it (as it is on overlay fs), will not accomplish much (changes
are not persisted to the underlying medium), upgrade should not fail.

Regards,
Witold