Apparently SIGPWR is used by lxc-stop to shut down LXC containers. What interface would you recommend instead?
https://lists.linuxcontainers.org/pipermail/lxc-users/2015-May/009279.html 2016-07-18 12:36 GMT+02:00 Lennart Poettering <[email protected]>: > On Sat, 16.07.16 17:22, Christian Hofstaedtler ([email protected]) wrote: > >> Hi, >> >> I'm trying to understand how sigpwr.target is intended to be used, >> but couldn't find a good explanation. systemd.special says this >> target is invoked in a power fail situation, but what should happen >> then? >> >> Debian, Ubuntu and PLD install "sigpwr-container-shutdown.service", >> which for ConditionVirtualization=container runs systemctl >> --no-block poweroff, i.e. triggers a shutdown for containers. For >> "normal" hardware, nothing appears to be triggered. >> >> I could not find any services installed by Fedora or openSuSE, but >> maybe I was looking in the wrong places. >> >> I'm now somewhat assuming there should be a default "policy" service >> that causes sigpwr.target to initiate a shutdown? >> >> Pointers/hints on what is expected behaviour from sigpwr.target >> would be highly appreciated. > > My recommendatin: don't bother with SIGPWR. Traditionally on UNIX UPS > software sends SIGPWR to PID 1 to initiate some special kind of > shutdown operation. But it's very vaguely defined only, and one > wonders why a normal shutdown isn't enough here, and why to bounce > this off PID 1 with a special UNIX signal even... > > I am pretty sure that power management software that runs in userspace > really shouldn't make use of this anymore. It should just request a > normal shutdown. The only reason why one would want to bother with > SIGPWR at all is that some really power-related old kernel drivers > send SIGPWR to PID 1 too. > > From the systemd PoV: this stuff is ugly legacy crap that only exists > for historic reasons and was never really well-defined in its > behavour. It mostly appears to be a concept that exists only because > Linux never had a useful IPC that was accessible from both kernelspace > and userspace in a sane way... In systemd, we don't want anything to > do with it, but some legacy folks really think it's superduper > important. Hence we simply map it to a target unit, and enable users > to map it to whatever they want to map it, but don't do anything smart > about it at all on our own. > > I think it would be best of people would just forget about it... > > Lennart > > -- > Lennart Poettering, Red Hat > _______________________________________________ > systemd-devel mailing list > [email protected] > https://lists.freedesktop.org/mailman/listinfo/systemd-devel -- Why is it that all of the instruments seeking intelligent life in the universe are pointed away from Earth? _______________________________________________ systemd-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/systemd-devel
