[Bug 1812863] Re: No way to debug grub.cfg generation

[Mathieu Trudel-Lapierre]

Verification-done on bionic with grub2 / grub2-signed:

iF grub-efi-amd64 2.02-2ubuntu8.10 amd64 GRand Unified Bootloader, version 2 (EFI-AMD64 version)
ii grub-efi-amd64-bin 2.02-2ubuntu8.10 amd64 GRand Unified Bootloader, version 2 (EFI-AMD64 binaries)
ii grub-efi-amd64-signed 1.93.11+2.02-2ubuntu8.10 amd64 GRand Unified Bootloader, version 2 (EFI-AMD64 version, signed)


ubuntu at ubuntu:/boot$ sudo update-grub
Sourcing file `/etc/default/grub'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-4.15.0-44-matt
Found linux image: /boot/vmlinuz-4.15.0-44-generic
Found initrd image: /boot/initrd.img-4.15.0-44-generic
grub-probe: error: cannot find a GRUB drive for /dev/sdb1.  Check your device.map.
Found Windows Boot Manager on /dev/sda1@/EFI/Microsoft/Boot/bootmgfw.efi
Adding boot menu entry for EFI firmware configuration
done


** Tags removed: verification-needed-bionic
** Tags added: verification-done-bionic

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https://bugs.launchpad.net/bugs/1812863

Title:
  No way to debug grub.cfg generation

Status in grub2 package in Ubuntu:
  Fix Released
Status in grub2 source package in Bionic:
  Fix Committed
Status in grub2 source package in Cosmic:
  Fix Committed

Bug description:
  [Impact]
  Any user who wants to understand how /boot/grub/grub.cfg is being generated. This is especially useful on dynamically-deployed systems (ie. using MAAS, cloud-init) on clouds or datacenter deployments.

  [Test case]
  1) Run 'update-grub'
  2) Verify that messages are displayed to describe which files are being read:

  $ sudo update-grub 
  Sourcing file `/etc/default/grub'
  Generating grub configuration file ...
  [...]

  
  [Regression potential]
  Watch out for any issues generating a correct and/or complete grub.cfg for next boot; missing kernels in the boot menu, or any missing kernel command-line parameters for a kernel booted after grub.cfg has been regenerated.

  ---

  It's really hard to debug what happens to generate grub.cfg -- no way
  to know what files (from /etc/default/grub, /etc/default/grub.d/*) are
  being used in which order.

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