Re: Some suggestions about s6 and s6-rc

From: Steve Litt <slitt_at_troubleshooters.com>
Date: Sun, 20 Sep 2015 12:03:06 -0400

On Sun, 20 Sep 2015 11:26:00 +0200
Laurent Bercot <ska-supervision_at_skarnet.org> wrote:

> On 20/09/2015 07:30, Steve Litt wrote:
> > Yes. The use of a file called "down" to tell the system not to run
> > the process, and also the use of a script called "down" to perform
> > an action at the appropriate time, will be holy hell to document,
> > even if theoretically they cannot both happen in the same script
> > directory.
>
> I don't think so. The confusion happened here because we're talking
> in a vacuum; when you use the tool, it's clear enough. You'll see.

That's my point exactly. Unfamiliar with the tool, you read the docs,
keep reading about "down" in two different contexts, get confused, and
say "later days."

And then there's this: What is to be gained by using the same filename
in two different contexts? Other than some global search and replace,
what would be the cost of changing "./down" to something more
descriptive?

Earlier in this thread, you yourself said:

> I agree that the name collision is confusing, and it is an annoyance.

If *you* think it's confusing, imagine the poor guy wanting a systemd
alternative not called "sysvinit", who has heard that s6-rc + s6 (do I
have that right?) is the best there is?

Or how bout the poor daemontools familiar admin who's heard that s6-rc
+ s6 is the best and it's daemontools-inspired, so he goes in with a
long-established understanding of "down" files and encounters this?

Giving this file a better name is a couple days of thought and an hour
of global search and replace. I think it's well worth it.

> > Also, don't be sure that they can't happen in the same script
> > directory. LittKit uses daemontools-style "down" files for both
> > oneshots and longruns, and there are probably other workarounds out
> > there that do the same thing. They'll all break upon the
> > introduction of a script called "down".
>
> They won't with s6-rc. A definition directory is not a service
> directory. Your scripts will work, don't worry.

OK, then I'm not correctly envisioning what s6-rc really is.

SteveT

Steve Litt
August 2015 featured book: Troubleshooting: Just the Facts
http://www.troubleshooters.com/tjust
Received on Sun Sep 20 2015 - 16:03:06 UTC

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