[systemd-devel] sd-boot and boot counting

[Andrei Borzenkov]

On Fri, Jul 4, 2025 at 8:19 AM Tristan Vroom <tristan.a.vroom at gmail.com> wrote:
>
> Hi,
>
> I am looking over the documentation about boot counting and I am trying to figure out how it works exactly.

https://systemd.io/AUTOMATIC_BOOT_ASSESSMENT/

> If I understand correctly, in order to enable it you have to write a number to /etc/kernel/tries, right?

To enable boot counting for a specific loader entry you just need to
rename it. /etc/kernel/tries simply adds the boot counter to every new
loader entry. It will not change existing entries.

 > I tried playing around with bless boot and changing sd-boot boot
entries by adding *+x-y.conf and bless-boot just marked it as good and
reset the configuration to *.conf and bless-boot now say it is clean,
not good.

What do you mean by "not good"? That is exactly what bless-boot is
supposed to do. If boot reaches systemd-bless-boot.service it is
assumed that this boot entry is good and needs no boot counting
anymore.

 > I am assuming I need to use kernel-install to get it to "stick".