systemd-bless-boot.service, systemd-bless-boot — Mark current boot process as successful
systemd-bless-boot.service
/usr/lib/systemd/systemd-bless-boot
systemd-bless-boot.service is a system service that marks the current boot process as
successful. It's automatically pulled into the initial transaction when
systemd-bless-boot-generator(8)
detects that systemd-boot(7) style
boot counting is used.
Internally, the service operates based on the LoaderBootCountPath EFI variable (of the
vendor UUID 4a67b082-0a4c-41cf-b6c7-440b29bb8c4f), which is passed from the boot loader to the
OS. It contains a file system path (relative to the EFI system partition) of the Boot Loader Specification compliant boot loader entry
file or unified kernel image file that was used to boot up the
system. systemd-bless-boot.service removes the two "tries done" and "tries left" numeric boot
counters from the filename, which indicates to future invocations of the boot loader that the entry has completed
booting successfully at least once. (This service will hence rename the boot loader entry file or unified kernel
image file on the first successful boot.)
The /usr/lib/systemd/systemd-bless-boot executable may also be invoked from the
command line, taking one of the following command arguments:
status¶The current status of the boot loader entry file or unified kernel image file is
shown. This outputs one of "good", "bad",
"indeterminate", "clean", "dirty", depending on
the state and previous invocations of the command. The string "indeterminate" is
shown initially after boot, before it has been marked as "good" or "bad". The string
"good" is shown after the boot was marked as "good" with the good
command below, and "bad" conversely after the bad command was invoked. The string
"clean" is returned when boot counting is currently not in effect (which includes
the case where the current entry was already marked as persistently good). The string
"dirty" is returned when the system is booted up with a known-bad kernel (i.e. one
where the tries left counter has previously reached zero already).
This command is implied if no command argument is specified.
good¶When invoked, the current boot loader entry file or unified kernel image file will be marked as
"good", executing the file rename operation described above. This command is intended to be invoked at the end
of a successful boot. The systemd-bless-boot.service unit invokes this
command.
bad¶When called the "tries left" counter in the boot loader entry file name or unified kernel image file name is set to zero, marking the boot loader entry or kernel image as "bad", so that the boot loader will not consider it anymore on future boots (at least as long as there are other entries available that are not marked "bad" yet). This command is normally not executed, but can be used to instantly put an end to the boot counting logic if a problem is detected and persistently mark the boot entry as bad.
indeterminate¶This command undoes any marking of the current boot loader entry file or unified
kernel image file as good or bad. This is implemented by renaming the boot loader entry file or
unified kernel image file back to the path encoded in the LoaderBootCountPath EFI
variable. Note that operation will fail if the current kernel is not booted with boot counting
enabled (i.e. if the EFI variable is not set). If the boot counter already reached zero tries left on
a previous boot this operation will fail too: once an entry is marked bad it can
only be reset to good again, but not to indeterminate.
-h, --help¶--version¶