supervision - discussion about system services, daemon supervision, init, runlevel management, and tools such as s6 and runit
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From: Ihor Antonov <ihor@antonovs.family>
To: Laurent Bercot <ska-supervision@skarnet.org>
Cc: "supervision@list.skarnet.org" <supervision@list.skarnet.org>
Subject: Re: s6-rc as user service manager
Date: Mon, 17 Oct 2022 20:12:13 -0700	[thread overview]
Message-ID: <20221018031213.xa3bluhrx5m45jss@localhost> (raw)
In-Reply-To: <em4bcac4b1-7e2a-4865-a308-61ed57e296c2@5fe6640a.com>

On 2022-10-18 00:58, Laurent Bercot wrote:
> > By testing I meant checking if the directory has an active process
> > watching it. I believe there is a function in skalibs  fd_lock [1]
> > that svscan uses to check if another svscan runs there. I think it is
> > just a matter of exposing that function as standalone executable.
> 
>  There are no executables to test whether s6-svscan or s6-rc are
> running on a given directory, because these are not dynamic properties.
> By policy, decided by you or your distro, you should *know*, at all
> times, whether a given directory is a scandir with an s6-svscan running
> on it - or whether a given directory is a livedir with s6-rc running
> on it.
>  If you think a given directory should have an s6-svscan running on it,
> then you're right; ensure that s6-svscan is started at boot time, and
> write your scripts assuming that it's there. If something fails because
> it's not there, that's a bug or a system problem, and needs to be fixed,
> not accommodated by your scripts.
> 

These tests made sense in the situation of user's services as systemd
does it. (Like answering a question whether another login shell has
already spawned svscan) It is indeed not necessary with static user
tree.

Ihor

      reply	other threads:[~2022-10-18  3:11 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-17 17:50 Ihor Antonov
2022-10-17 20:42 ` Peter Shkenev
2022-10-17 23:49   ` Ihor Antonov
2022-10-18  0:58     ` Laurent Bercot
2022-10-18  3:12       ` Ihor Antonov [this message]

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