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Re: [Condor-users] condor cron
- Date: Wed, 2 Sep 2009 08:35:00 -0500
- From: Alain Roy <roy@xxxxxxxxxxx>
- Subject: Re: [Condor-users] condor cron
The argument for the existence of Condor cron is that Condor cron is
managed while cron is not.
Cron is a simple tool that everyone is familiar with, but it puts the
burden of proper job management onto users. For example (and this is a
real example from my personal experience), let's say you have a job
that runs every 5 minutes. It runs quickly--you're sure of it. But
something happens. Perhaps the system is loaded, perhaps the shared
filesystem becomes completely sluggish. Suddenly your quick job takes
a really long time to run, much more than five minutes. What happens?
Cron doesn't care but it keeps re-running your job every five minutes,
only adding to the load and worsening the problem. Did you program
your job to be resilient to running more than once? Cron is "fire and
forget", while Condor cron is not. Condor cron will not overlap jobs
like that, and it will also allow you to apply Condor's policies to
jobs. For example, you can kill the Condor cron jobs if the system
load is too high.
Also, traditional cron implementations are bad about scheduling. What
if you specify that your job should be run at 1:00am each day, but the
computer happens to be down at that time? Condor cron can deal with
Condor cron mixes well with the local universe, which runs jobs on the
On Sep 2, 2009, at 6:34 AM, Mag Gam wrote:
So, why not use use cron? Instead of using a built in feature?
On Tue, Sep 1, 2009 at 11:27 PM, Joe Meehean<jmeehean@xxxxxxxxxxx>
This part of the manual may be useful for you:
Essentially, Condor allows jobs to be run
periodically, mimicing features provided by cron.
Mag Gam wrote:
I was wondering if there were best practices for condor and cron.
Several of our students would like to submit condor jobs via cron
nightly, and I was wondering what is the best way to do this?
Is it simple as script.sh which will have condor_submit submitfile?
Or something more to it?