Re: runit SIGPWR support

From: Jan Braun <>
Date: Fri, 28 Feb 2020 07:39:47 +0100

innerspacepilot schrob:
> I have checked openrc and busybox - both support SIGPWR.
> So I see no reason to change lxd behaviour, unless some realworld
> software uses SIGPWR.

*sigh* We've been here before.
The Linux kernel uses SIGPWR to tell init "there's a power failure
imminent". There's a difference to "please shutdown the system", even if
(current versions of) busybox and openrc choose to shutdown the system
when told about an imminent power failure.

Laurent (imho correctly) argues that e.g. suspend-to-disk would be a
better reaction when faced with an imminent power failure, and therefore
refuses to declare that his init will shutdown the system when getting

The people who think adjusting lxc.signal.halt is too much effort would
like inits to standardize on a signal for initiating shutdown. That
would indeed be nice.
But the only (catchable) signal that's out of the question for that
purpose is, indeed, SIGPWR. Because the most relevant realworld
software, the Linux kernel itself, has already fixed SIGPWR for a
different purpose.


Received on Fri Feb 28 2020 - 06:39:47 UTC

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