Re: [PLUG] LINUX ADMIN ADVICE

[Rich Kulawiec <rsk@gsp.org>]

On Thu, Aug 02, 2018 at 07:23:07AM -0400, Rich Freeman wrote:
> Sure, but while you're busying fixing bugs it doesn't hurt to have the
> service still running, vs paying somebody to babysit it, or writing
> custom scripts to babysit stuff for you.

Restarting a service which has provided a demonstration proof that it's
broken isn't a good operational practice.  It *does* hurt to have it
still running.  It should be shut down until such time as the problem
is reproduced, isolated, understood, debugged, and fixed.

> Proving that your software doesn't have bugs is a near-impossible
> task.  Defense in depth makes a lot more sense.  And as I mentioned
> systemd does a lot more than just restart services.

1. Blindly restarting a failed service isn't a "defense" of any kind.
It's wishful thinking.

2. I'm well aware that systemd "does a lot more".  But that's not
a feature.  That's a catastrophic design blunder, one which is obvious to
anyone with even a rudimentary grasp of the "Software Tools" and
Unix philosophies.

3. You do know that this isn't my first day on the job, yes?

> IMO if your requirements are so simple that rc.local does everything
> you need, there is a good chance that rc.local is already too complex
> for you.  Why not just make init a bash script?

I think you're missing the point.  If your requirements, for a value
of "you" meaning "pretty much all of you", aren't that simple or nearly
so, then you're probably doing it wrong.  The solution to that isn't
to layer on yet more complexity, it's to step back, re-evaluate the design,
and consider how it could be done more elegantly, simply, and robustly.

This requires more work.  It may require throwing things away that had
substantial effort invested in them.  It sometimes requires going back to
a blank whiteboard.  It may be tedious and expensive.  But it's what I'd
expect competent professionals to do.

---rsk
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