[Pacemaker] crond on both nodes (active/passive) but some jobs on active only

Lars Ellenberg lars.ellenberg at linbit.com
Fri Jul 5 16:12:30 EDT 2013


On Fri, Jul 05, 2013 at 04:52:35PM +0200, andreas graeper wrote:
> when i wrote a script handled by ocf:heartbeat:anything i.e. that is
> signalling the cron-daemon to reload crontabs
> when crontab file is enabled by symlink:start and disabled by symlink:stop
> 
> how can i achieve that the script runs after symlink :start and :stop ?
> when i define order-constraint R1 then R2 this implizit means R1:start ,
> R2:start and R2:stop, R1:stop ?
> 

Not an answer to that specific question,
rather a "why even bother" suggestion:

You say:
> > two nodes active/passive and fetchmail as cronjob shall run on active only.

How do you know the node is "active"?
Maybe some specific file system is mounted?
Great.  You have files and directories
which are only visible on an "active" node.

Why not prefix your cron job lines with
test -e /this/file/only/visible/on/active || exit 0; real cron command follows
 or
cd /some/dir/only/on/active || exit 0; real cron command

 or a wrapper, if that looks too ugly
only-on-active real cron command

/bin/only-on-active:
#!/bin/sh
same-active-test-as-above || exit 0
"$@" # do the real cron command

	Lars

> 2013/7/5 andreas graeper <agraeper at googlemail.com>
> 
> > hi,
> > two nodes active/passive and fetchmail as cronjob shall run on active only.
> >
> > i use ocf:heartbeat:symlink to move / rename
> >
> > /etc/cron.d/jobs <> /etc/cron.d/jobs.disable
> >
> > i read anywhere crond ignores files with dot.
> >
> > but new experience: crond needs to restarted or signalled.
> >
> > how this is done best within pacemaker ?
> > is clone for me ?
> >
> >
> > thanks in advance
> > andreas


-- 
: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

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