Re: Describing daemontools in 300 words?

From: Steve Litt <slitt_at_troubleshooters.com>
Date: Fri, 12 Jun 2015 21:19:54 -0400

On Sat, 13 Jun 2015 02:27:12 +0200
Laurent Bercot <ska-supervision_at_skarnet.org> wrote:

> On 13/06/2015 02:21, Steve Litt wrote:
> > If you had to describe daemontools, in the context of a general
> > purpose process manager, to a technical person, in 300 words, what
> > things would you say and what things would you leave out?
>
> At this point I have to ask: are you using "daemontools" as a
> generic name for supervision suites, or as the original suite from
> DJB? If the latter, why are you advertising it over s6 or runit,
> which provide the same functionality but are actually maintained ?

Good question.

For my current, almost finished project, I need a process manager, not
a whole init system. Daemontools works every time and I know it well.
Same with daemontools-encore, which I'm getting to like better than the
original.

I haven't used runit for awhile, but as I remember it's more complex,
possibly because I used it as a whole init. When I tried S6 about 8
months ago (and I knew a lot less then), I was unable to get it
installed and running. As far as nosh, once I compiled it I didn't know
what to do with it, and the nosh language remains an enigma to me,
although I understand I can program its runscripts in sh also.

>
> (I'm not asking out of spite, I'm asking because if there's
> something you find in daemontools that you don't find in s6, I want
> to add it.

:-) I think you'd have to subtract it. Daemontools and daemontools
encore are simple and have a very small number of features. And I
completely understand what they do.

For instance, when you and Gerrit get to discussing
whether /etc/runit/1 should have the same PID as /etc/runit/2, I try to
follow both your logics (I can't remember right now which supports
which option), but I can't keep up. With, let's say,
daemontools-encore, I know I'm dealing with the equivalent
of /etc/runit/2, and my Suckless Init is /etc/runit/1. I just
understand it better, and in my case they're separate PIDs (and no,
right now Suckless Init doesn't REspawn daemontools-encore).

You know what it is? Daemontools-encore is a better learning tool
because it's simpler. When I get ready to actually lay down a real init
on my daily driver desktop, it won't be Suckless Init with daemontools
encore and LittKit, it will be runit or S6 or possibly Epoch (which
isn't a daemontools inspired init).


> I've gone far to make sure s6 was an improvement over
> daemontools in every possible way, and if I have missed something, I
> want to know.)
>

:-)

I think you've missed that it's hard to make a superset and keep it as
easy for learning as the subset. It's just the nature of the beast.

So let me rephrase with something that *is* being maintained:

How would you describe the process manager (not init)
daemontools-encore, to a technical person, in 300 words.

Thanks,

SteveT

Steve Litt
June 2015 featured book: The Key to Everyday Excellence
http://www.troubleshooters.com/key
Received on Sat Jun 13 2015 - 01:19:54 UTC

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