Re: Readiness notification exemplars

From: Serge E. Hallyn <>
Date: Sat, 4 Apr 2020 10:48:51 -0500

On Fri, Apr 03, 2020 at 07:41:25AM +0000, Jonathan de Boyne Pollard wrote:
> Serge E. Hallyn:
> > If making changes to daemons were going to palatable, [...]
> >
> Clearly, it *is* palatable, given that a few people have been adding the
> systemd mechanism to their programs for several years, now. Pierre-Yves

Well both that and the less successfull upstart sigstop had the full force
of popular distros behind them. Still I hope you're right, and maybe I'll
go ahead and post some patches for a few daemons.

> Ritschard's code and Cameron Norman's code come straight out of actual
> service programs.

> Serge E. Hallyn:
> > you are arguing for parsing stdout for a text message and/or using
> > pidfiles (written to an fd)
> >
> No, M. Bercot is not. Quite the opposite, in fact. The s6 readiness
> mechanism demands *neither* pidfiles *nor* standard output. It's *any* file
> descriptor (as defined by the service), and *just a linefeed* followed by
> closing the descriptor.
> I'm nodding at almost everything M. Bercot is saying here, by the way.
> *

Yes it sounds like I completely misread the earlier emails, sorry about
that. Now, looking at,
I'm probably not reading that quite right, but it seems to tie the
proposal to the 'notifcation-fd' file in the service directory, making
it a bit less general. s6-log however uses the -d argument to pass the
fd, so I'll go with that.

Received on Sat Apr 04 2020 - 15:48:51 UTC

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