[CentOS] cron.hourly runs twice

Jason Pyeron jpyeron at pdinc.us
Wed Mar 17 14:13:12 UTC 2010


 

> -----Original Message-----
> From: centos-bounces at centos.org 
> [mailto:centos-bounces at centos.org] On Behalf Of Michael Schumacher
> Sent: Wednesday, March 17, 2010 9:00
> To: CentOS mailing list
> Subject: Re: [CentOS] cron.hourly runs twice
> 
> Timothy,
> 
> On Wednesday, March 17, 2010 you wrote:
> 
> >>> For some reason I cannot fathom,
> >>> cron.hourly runs twice each hour
> >>> on one of my two CentOS-5.4 systems,
> 

Need to get a look into the runtime environment:

Add this to the cron.hourly

#!/bin/sh
pstree -up >> /tmp/foo.log

Next hour look at the parents (and their pids).

> Here comes a very weird idea. I don't know the internals of 
> the cron-daemon good enough to know if this can actually happen.
> If you have a NTP-job every hour started by cron that 
> corrects the internal time and if your internal clock runs 
> too fast, the system time may be reset every hour so that the 
> cron-job will start twice. As I said, I don't know if 
> cron-daemon has a mechanism that would avoid that problem.
> 
> 
> best regards
> ---
> Michael Schumacher
> PAMAS Partikelmess- und Analysesysteme GmbH Dieselstr.10, 
> D-71277 Rutesheim Tel +49-7152-99630 Fax +49-7152-996333
> Geschäftsführer: Gerhard Schreck
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> 
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> 


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