Re: s6-rc shutdown timing issue

From: Colin Booth <cathexis_at_gmail.com>
Date: Sun, 13 Sep 2015 20:44:39 -0700

On Sun, Sep 13, 2015 at 2:34 PM, Laurent Bercot <ska-skaware_at_skarnet.org> wrote:
>
> I'm afraid there's no real solution to the stragglers problem, and the
> only safe approach is to keep everything mounted all the time and only
> perform the unmounts in stage 3 after everything else has been done and
> the processes have been killed.
>
Yeah, the asymmetry is annoying, but all the other options are worse.
Sounds like current best practices should be to keep rw->ro remounts
out of s6-rc (at least / and /var), call `s6-rc -da change' before
signalling s6-svscan, and then explicitly do those remounts in stage
3. Like I said, not great but better than the alternatives, and a lot
less magic than it could be.
>
> In other news, I'm now in the process of testing s6-rc-update. I've
> finished brooming the obvious bugs, now is the most annoying part: so
> many test cases, so many things that can go wrong, and I have to try
> them one by one with specifically crafted evil databases. Ugh. I said
> I'd release that thing in September, but that won't happen if I die of
> boredom first.
> If you're totally crazy, you can try running it, but unless you're
> doing something trivial such as switching to the exact same database,
> chances are that something will blow up in your face - in which case
> please let me analyze the smoke and ashes.
>
When I've got some time I'll spin up a vm and let you know what the
disaster looks like. What do you want in terms of debuging? I'm
assuming old and new service databases at the minimum. Odds are they
won't be nearly as terrible as your custom-built databases, but who
knows.

Cheers!


-- 
"If the doors of perception were cleansed every thing would appear to
man as it is, infinite. For man has closed himself up, till he sees
all things thru' narrow chinks of his cavern."
  --  William Blake
Received on Mon Sep 14 2015 - 03:44:39 UTC

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