openSUSE MicroOS is a snapshot-based, immutable operating system that features automatic updates and recovery.
health-checker is the system tool responsible for handling automatic recovery and rollbacks, and it comes installed by default. It was recently rewritten to support both systemd-boot and grub2-bls, utilizing systemd-bless-boot and Automatic Boot Assessment.

In this talk, we will provide a brief explanation of the Boot Loader Specification (BLS), which is supported by both systemd-boot and grub2-bls. Next, we will explain Automatic Boot Assessment, describe how it is used by health-checker, and show how it can be used to check the system status at boot and act accordingly.