** Description changed: [Impact] GCE cloud instances started with images released prior to 2020-11-11 will fail to reboot when the newest grub2 2.02~beta2-36ubuntu3.32 packages are installed from -updates. Upon reboot, the instance drops down to a grub prompt, and ceases to boot any further. The output displayed is: BdsDxe: loading Boot0003 "debian" from HD(15,GPT,<UUID>,0x2800,0x35000)/\EFI\debian\shimx64.efi BdsDxe: starting Boot0003 "debian" from HD(15,GPT,<UUID>,0x2800,0x35000)/\EFI\debian\shimx64.efi UEFI: Attempting to start image. Description: debian FilePath: HD(15,GPT,36903981-58D9-4718-A4EC-3D3E6CF6AF42,0x2800,0x35000)/\EFI\debian\shimx64.efi OptionNumber: 3. GNU GRUB version 2.04 grub> Now, on GCE cloud images prior to 2020-11-11, /etc/default/grub.d/50 -cloudimg-settings.cfg contained this line: GRUB_DISTRIBUTOR=Debian In images after 2020-11-11, this line was REMOVED from /etc/default/grub.d/50-cloudimg-settings.cfg and instead, images fell back to the below line in /etc/default/grub GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian` The above line always returns "Ubuntu". - The new grub2 version 2.02~beta2-36ubuntu3.32 now places the EFI - executables in the /EFI/Ubuntu directory, while the grub config points - to /EFI/Debian, and the grub config cannot be found, and hence we drop - to a grub shell. + The new grub2 version 2.04-1ubuntu44 now always looks for the grub.cfg + in /EFI/ubuntu, with no fallback to look in the directory the EFI grub + executable was booted from. Since GRUB_DISTRIBUTOR=Debian means the + grub config is only written to /EFI/debian/grub.cfg, the new grub fails + to find its config despite being booted from /EFI/debian/grubx64.efi, + and hence we drop to a grub shell. [Testcase] You can start an instance up on Google Cloud with an affected image with the below command: gcloud compute instances create test-xenial-1 --image=ubuntu-1604-xenial-v20200429 --image-project=ubuntu-os-cloud From there: $ sudo apt update $ sudo apt install grub-common grub-efi-amd64 grub-efi-amd64-bin grub-efi-amd64-signed grub-pc-bin grub2-common $ sudo reboot The instance will not come back up, and you will see a grub shell in the logs on GCP. You can also reproduce in KVM. Simply add: GRUB_DISTRIBUTOR=Debian to a file in /etc/default/grub.d/50-cloudimg-settings.cfg then: $ sudo update-grub $ sudo reboot Test packages are available in the following ppa: https://launchpad.net/~mruffell/+archive/ubuntu/lp1928040-test If you install these test packages, you should be able to upgrade grub and reboot without issue. [Where problems could occur] We will be changing the grub configuration for every Google cloud instance started with an image produced before 2020-11-11, and there is risk that we could make a change which prevents instances from booting. We should proceed with caution and make sure to test older and newer images. The fix will be targeted to the /etc/default/grub.d/50-cloudimg- settings.cfg file only, so only cloud instances would get the change, and only if the grub versions match particular versions. [Other info] A workaround is to remove the below line from /etc/default/grub.d/50 -cloudimg-settings.cfg before installing the new grub packages. GRUB_DISTRIBUTOR=Debian
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1928040 Title: GCE instances drop to a grub prompt when GRUB_DISTRIBUTOR=Debian is set To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2-signed/+bug/1928040/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
