NAME¶

health-checker, health-checker.service - Checks that all important services of a system did come up correctly after an update and reboot.

SYNOPSIS¶

/usr/sbin/health-checker

/usr/sbin/health-checker --version

health-checker.service

DESCRIPTION¶

health-checker checks if the system is coming up correctly during boot up. The behavior depends if the system is using systemd-boot/grub2-bls or legacy grub2.

With systemd-boot/grub2-bls: the bootloader picks the first available entry and health-checker checks that the system has booted successfully. When any plugin fails, then health-checker will behave depending on the entry booted: if it is a snapshot that has previously been booted successfully then health-checker will try rebooting the system once more, and it will open an emergency shell if the system still fails to boot. If this is the first boot of a new snapshot, then the system will reboot a number of timed configured in /etc/kernel/tries, checking the status each time. If the system stills fails to boot, then health-checker marks the current entry as not working and reboot. The bootloader will pick the next available boot entry. It is possible to disable health-checker automated rebooting by adding "health-checker-reboot=disabled" to the kernel cmdline.

In case of an error and legacy grub2 is used, the remediation action depends on what happened before. If this is the first boot after a transactional update, an automatic rollback to the last known working snapshot is executed. If the snapshot was already rebooted successfully before, a reboot is tried. If this does not help, some services are shutdown and an admin has to repair the system.

If the boot was successful, the current snapshot is marked as known to be working.

Plugins are used for performing the tests and new plugins can be written. They are stored in the /usr/libexec/health-checker or /usr/local/libexec/health-checker (individual user plugins) directory and are executed either with the option check or stop. If called with "check", the plugin should verify that the service works and return 0, else 1. If one plugin returns "1", health-check will evaluate what to do. If neither a rollback or reboot is usefull, all plugins will be called with the "stop" option. In this case, the plugins should shutdown the services are far as possible and usefull.

TELEMETRY¶

If telem-record-gen(1) is installed telemetry events are created additional to logging with syslog(3).

SEE ALSO¶

transactional-update(8)

AUTHOR¶

Thorsten Kukuk <kukuk@suse.de>