[systemd-devel] Antw: Re: Antw: Re: [EXT] Re: Run "ipmitool power cycle" after lib/systemd/system-shutdown scripts

[Ulrich Windl]

>>> Mantas Mikulenas <grawity at gmail.com> schrieb am 10.02.2022 um 14:15 in
Nachricht
<CAPWNY8Wa_hgNJbu-D-16_BE+DXuKSSvukfhirM9odDXBg881DA at mail.gmail.com>:
> On Thu, Feb 10, 2022 at 3:11 PM Ulrich Windl <
> Ulrich.Windl at rz.uni-regensburg.de> wrote:
> 
>> >>> Etienne Champetier <champetier.etienne at gmail.com> schrieb am
>> 10.02.2022 um
>> 12:47 in Nachricht
>> <CAOdf3grZ2wUOkJ8Pzu-EM=+ZCKY4b6XK9dyZoh=QpX5HgHJfxA at mail.gmail.com>:
>> > Le jeu. 10 févr. 2022 à 11:49, Ulrich Windl
>> > <Ulrich.Windl at rz.uni-regensburg.de> a écrit :
>> >>
>> >> >>> Lennart Poettering <lennart at poettering.net> schrieb am 10.02.2022
>> um
>> 11:31
>> >> in
>> >> Nachricht <YgTpdVFRgL+uQoY9 at gardel-login>:
>> >> > On Mi, 09.02.22 22:05, Etienne Champetier (
>> champetier.etienne at gmail.com)
>> >> > wrote:
>> >> >
>> >> >> Hello systemd hackers,
>> >> >>
>> >> >> After flashing the firmware of some pcie card I need to power cycle
>> >> >> the server to finish the flashing process.
>> >> >> For now I have a simple script in lib/systemd/system-shutdown/
>> running
>> >> >> "ipmitool power cycle" but I would like to make sure it runs after
>> >> >> other scripts like fwupd.shutdown or mdadm.shutdown
>> >> >>
>> >> >> Is there any way to have systemd cleanly power cycle my server
>> instead
>> >> >> of rebooting it ?
>> >> >
>> >> > What does "power cycle" entail that "reboot" doesnt? i.e. why doesn't
>> >> > "systemctl reboot" suffice?
>> >>
>> >> My guess is that some smart cards with their own firmware and CPu do
not
>> >> reboot unless they are power cycled, so maybe if the firmware upgrade
on
>> the
>> >> card does not force it to reboot, it my need a power cycle.
>> >>
>> >> >
>> >> > /usr/lib/systemd/system-shutdown/ drop-ins are executed before the OS
>> >> > transitions back into the initrd — the initrd will then detach the
>> >> > root fs (i.e. undo what it attached at boot) and actually reboot.
This
>> >> > means if your command turns off the power source you should stick it
>> >> > in the initrd's shutdown logic, and not into
>> >> > /usr/lib/systemd/system-shutdown/. If you are using RHEL this means
>> >> > into dracut. But adding it there is something to better discuss with
>> >> > the dracut community than here.
>> >>
>> >> My guess is that it would be handled best by some special GRUB boot
>> menu
>> > entry
>> >> (like "boot 'power cycle' once).
>> >
>> > This is pretty clean but it means going through "BIOS" init twice
>> > which can be pretty long on physical servers
>>
>> Hi!
>>
>> Of course I have a better solution: Use an external server and just before
>> restarting send a command to that server that will, after a carefully
tuned
>> delay, will trigger the IPMI power-cycle remotely ;-)
>> I believe that it's almost impossible to trigger a power cycle through
IPMI
>> while also doing a clean shutdown/reboot, unless the the IPMI features a
>> delayed execution itself.
>>
> 
> Asking the BMC to power the system off is no different than asking the
> system to power itself off – what makes it a "clean shutdown" is stopping
> services, syncing and unmounting filesystems, etc. So in theory these
> shutdown hooks should do the job.
> 
> Though a better place would be a "shutdown initramfs" which runs from a
> tmpfs after *all* storage has been unmounted. I think Dracut has that, and
> explicitly specifies the order for its shutdown hooks, so it should be
> possible to put ipmitool there.

Another solution comes to my mind: How about programming the RTC for
time-based wakeup (say in 5 minutes from now), then "shutdown -h"...


> 
> -- 
> Mantas Mikulėnas