systemd-update-done.service, systemd-update-done - Mark /etc/ and /var/
       fully updated



       systemd-update-done.service is a service that is invoked as part of the
       first boot after the vendor operating system resources in /usr/ have been
       updated. This is useful to implement offline updates of /usr/ which might
       require updates to /etc/ or /var/ on the following boot.

       systemd-update-done.service updates the file modification time (mtime) of
       the stamp files /etc/.updated and /var/.updated to the modification time
       of the /usr/ directory, unless the stamp files are already newer.

       Services that shall run after offline upgrades of /usr/ should order
       themselves before systemd-update-done.service, and use the
       ConditionNeedsUpdate= (see systemd.unit(5)) condition to make sure to run
       when /etc/ or /var/ are older than /usr/ according to the modification
       times of the files described above. This requires that updates to /usr/
       are always followed by an update of the modification time of /usr/, for
       example by invoking touch(1) on it.

       Note that if the systemd.condition-needs-update= kernel command line
       option is used it overrides the ConditionNeedsUpdate= unit condition
       checks. In that case systemd-update-done.service will not reset the
       condition state until a follow-up reboot where the kernel switch is not
       specified anymore.

       systemd(1), systemd.unit(5), touch(1)

systemd 247                                       SYSTEMD-UPDATE-DONE.SERVICE(8)