openSUSE Tumbleweed recently changed the default boot loader from GRUB2 to GRUB2-BLS when installed via YaST.

This follows the trending started by MicroOS of adopting boot loaders that are compatible with the boot loader specification. MicroOS is using systemd-boot, a very small and fast boot loader from the systemd project.

One of the reasons of this change is that simplify the integration of new features, like a full disk encryption based on the systemd tools, that will make use of the TPM2 or FIDO2 tokens if they are available.

What is GRUB2-BLS

GRUB2-BLS is just GRUB2 but with some patches on top ported from the Fedora project, that includes some compatibility for the boot loader specification for Type #1 boot entries. Those are small text files stored in /boot/efi/loader/entries that the boot loader reads to present the initial menu.

Each file contains a reference to the kernel, the initrd and the kernel command line that will be used to boot the system, and can be edited directly by the user or managed by tools like bootctl and sdbootutil.

The next version of GRUB2 (2.14) those patches will be included as part of the project itself, and the upgrade process will be transparent for the final user.

Should be noted that the way that openSUSE deploy GRUB2-BLS is different from the classical GRUB2. GRUB2-BLS is deployed as a single EFI binary installed (copied) in /boot/efi/EFI/opensuse that will have embedded all the resources (like the modules, configuration file, fonts, themes and graphics) that previously where placed in /boot/grub2.

Installation

The good news is that with the last version of YaST the process is automatic. The used just needs to follow the default steps and the system will be based on GRUB2-BLS at the end.

The installed will propose first a large ESP partition of about 1GB. This is required because now all the kernel and initrds will be placed in the FAT32 ESP partition, in /boot/efi/opensuse-tumbleweed.

Of course the user can select during the installation a different boot loader, like the classical GRUB2 or systemd-boot. This can be done in the “Installation Settings” screen presented at the end of the installation proposal. Just select the “Booting” header link and choose your boot loader from there.

Usage

With GRUB2-BLS we will not have anymore the grub2 tools, like grub2-mkconfig or grub2-install. Most of them are not required anymore. The boot entries are generated dynamically by the boot loader, so there is no need anymore of generating GRUB2 configuration files, and the installation is just copying the new EFI file into the correct place.

The upgrade process is also done automatically calling sdbootutil update by the snapper plugins or the SUSE module tools, so if btrfs is used all the management will be done transparently by this infrastructure, as was done in the traditional boot loader.

Updating the kernel command line can be now be done by editing the boot loader, or the /etc/kernel/cmdline and calling sdbootutil update-all-entries to propagate the change into the boot entries of the current snapshot.

xthylacine hat dem Pool ein Foto hinzugefügt:

Looking a little bored at the moment . . .

Harajuku, Tokyo, Japan