自动启动评估#

systemd provides support for automatically reverting back to the previous version of the OS or kernel in case the system consistently fails to boot. The UAPI.1 Boot Loader Specification describes how to annotate boot loader entries with a counter that specifies how many attempts should be made to boot it. This document describes how systemd implements this scheme.

The many different components involved in the implementation may be used independently and in combination with other software to, for example, support other boot loaders or take actions outside of the boot loader.