Avoid UEFI GRUB entries on BIOS-booted guests#470
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petrutlucian94 merged 1 commit intoJul 10, 2026
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Signed-off-by: Mihaela Balutoiu <mbalutoiu@cloudbasesolutions.com>
| self._exec_cmd_chroot( | ||
| "sed -i '/cloud-init=disabled/d' %s" % grub_conf_disabler) | ||
| self._schedule_grub2_update() | ||
| contents = self._read_file_sudo(grub_conf_disabler) |
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Unrelated change but it seems useful, avoiding an unnecessary grub update.
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Please add a PR description, describing the problem and the solution. |
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Done |
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When OSMorphing runs from a UEFI-booted minion while migrating a BIOS-booted guest, the guest chroot still exposes the minion's
/sys/firmware/efi(the minion's/proc /sys /dev /runare bind-mounted into the chroot). Red Hat–family bootloader tooling detects that path and assumes the guest is UEFI-booted, so it generates UEFI-specific GRUB entries (linuxefi/initrdefi) for a BIOS guest.Since the BIOS GRUB (i386-pc) has no such commands, the guest fails to boot after migration:
error: can't find command 'linuxefi'error: can't find command 'initrdefi'Solution
Mask the minion's firmware in the guest chroot. When the migrated OS firmware type is BIOS and the minion exposes EFI firmware, mount a tmpfs over
/sys/firmwareinside the mounted guest root. This prevents tools running in the chroot (e.g.grub2-mkconfigvia/etc/grub.d/10_linux) from incorrectly detecting UEFI and emitting UEFI boot entries, so a BIOS guest getslinux16/initrd16.Avoid unnecessary GRUB regeneration. The cloud-init handling now regenerates
grub.cfgonly whencloud-init=disabledis actually present in/etc/default/grub, removing a gratuitousgrub2-mkconfiginvocation that widened exposure to this issue.