[Libguestfs] Re: virt-builder debian-12 --update failure

On Sun, Dec 10, 2023 at 09:42:04PM -0500, Stefan Hajnoczi wrote: > Hi, > virt-builder --update debian-12 fails with: > Setting up grub-pc (2.06-13+deb12u1) ... > grub-pc: Running grub-install ... > /dev/vda does not exist, so cannot grub-install to it! > You must correct your GRUB install devices before proceeding: > > DEBIAN_FRONTEND=dialog dpkg --configure grub-pc > dpkg --configure -a > dpkg: error processing package grub-pc (--configure): > installed grub-pc package post-installation script subprocess > returned error exit status 1 > > Any idea why /dev/vda isn't available to grub-install in virt-builder? > > I guess there might be some special guest device configuration for the > guestfs appliance that runs virt-builder steps, causing the device to > appear as something other than /dev/vda. virt-builder templates are generated using whatever default disk interface virt-install chooses: https://github.com/rwmjones/guestfs-tools/blob/master/builder/templates/d... which is probably virtio-blk. However the libguestfs appliance, where virt-builder does its updates etc, uses virtio-scsi. TBH I don't think this is solvable from virt-builder. I would either "hold" the grub-pc package (see below), or do the update as a firstboot operation, or try to get Debian to fix it in the grub-pc package, or maybe we could switch the template to use UEFI in future.