Re: automatically restarting dying daemons?
On Thu, Jul 01 at 05:59PM +0100, Thomas Adam wrote:
> --- Will Trillich <will@serensoft.com> wrote:
> > #!/bin/bash
> > /etc/init.d/some-daemon-here restart
>
> Better to use 'invoke-rc.d' here:
>
> invoke-rc.d <script> restart
for daemon-config-file-settings, i'm more comfortable specifying
the whole path. less chance of intervention or misdirection
based on $PATH mungings...
is invoke-rc.d similar to the "service" function on other
distros? (sarge already has a "_service" for bash to facilitate
command-line word completion... and i understand that the
"service" function/script/alias is on its way.)
and WHY is invoke-rc.d * better than /etc/init.d/*? and is that
reason still applicable for daemon configs? (don't you stick
with full path names in your cron jobs?)
> > which is effectively a "start-some-thing &" and quick
> > return...
> >
> > or does it need to be the non-returning call to the daemon
> > itself, so that the daemon is a child of the "supervise"
> > process? if so, ick.
>
> I'm not quite sure what you're asking here. There's no need to
> background that (rather pointless) wrapper script, since the
> daemon will fork if its own accord.
right. here's my question:
according to the not-so-very-loquacious documentation at
http://cr.yp.to/ --
"
supervise switches to the directory named s and starts
./run. It restarts ./run if ./run exits. It pauses for a
second after starting ./run, so that it does not loop too
quickly if ./run exits immediately.
"
looks like it's expecting ./run to be a long-duration process,
such as a database server itself, for example, that service will
then restart when the thing dies. it's NOT expecting (if i get
the gist of the english there) that this will be a quickie
"start a daemon somewhere else" because
1) there seems to be no facility for checking for a daemon
process, only the ./run process (i.e. child processes of
supervise)
2) when ./run exits immediately, supervise will re-launch it
(after waiting for a whole second) so our daemons will get
re-initialized sixty times a minute, and for something like
a database server, that's very much badness
unless i misunderstand, this seems to be a "run-and-monitor home
grown programs and scripts, do your system daemon resurrection
elsewhere"... no?
======
btw -- "restartd" seems to be just the item we're looking for.
it's a bit terse, too, but it monitors already-running items and
lets you specify a command to resurrect (or terminate)
accordingly. not too advanced, and needs better documentation,
but it works just fine -- at least, for us.
--
I use Debian/GNU Linux version 3.0;
Linux boss 2.4.18-bf2.4 #1 Son Apr 14 09:53:28 CEST 2002 i586 unknown
DEBIAN NEWBIE TIP #14 from Will Trillich <will@serensoft.com>
:
What's a RUNLEVEL? It's simply a big-time setting group;
runlevel 2 might have a full-blown web server plus X running,
and runlevel 3 might be ssh-only, for secure logins. Check
/etc/inittab (and /etc/rc<RUNLEVEL>.d/*) for details on how
yours are set up. And try "man runlevel".
Also see http://newbieDoc.sourceForge.net/ ...
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