[CentOS] Cron script crashing server...

Mon Oct 3 13:02:29 UTC 2005
Mark Belanger <mark_belanger at ltx.com>

Ian mu wrote:
 > Ok, weirder, thanks for the advice by the way, I guess its isolated it
 > somewhat and not where I thought it would be....added the strace, but
 > looks like not needed as never gets that far...


The next thing I would do is to attach strace to cron just before
it kicks off.  Make sure to capture the output - there will be a lot
of it. strace -p PIDofCron -f -o/path/somefile

You might also look at the cron file with an octal editor to make
sure there are no funny characters in it.  Or just create a brand
new one.

I would also look carefully each directory in the path and
the contents of them as well i.e.

ls -ld /home
ls -la /home
ls -ld /home/statsman
ls -la /home/statsman
ls -ld /home/statsman/stats
ls -la /home/statsman/stats

-Mark

 >
 > Piped the cron commandline to a file crondebug as mark suggested, its
 > created at cron run time, but empty.
 > 36 13 * * *
 >  >/home/statsman/stats/crondebug
 >
 > For the first line of the run_stats.sh (tried also with #!/bin/bash)
 > file it calls I added
 >
 > echo "stage 1" >> /home/statsman/stats/gendebug
 >
 > Run it manually from console it echos stage 1, (also echo stage 2 I
 > added, then after that the perl script is invoked) fine.
 >
 > Run from cron it never even does the echo "stage 1" to the file (or at
 > least doesn't create it).
 >
 > So it looks like its either dying on execing the file and not getting
 > any further as it never writes the first line of the simple bash script
 > or not even trying to call the file? (file gendebug isn't even created).
 >
 > More puzzled at this moment than I thought (nothing in root mail from
 > cron either btw, and rest of crontab seems ok, I leave the line in just
 > comment out the line with a single # and it doesn't crash ).
 >
 > Baffled :), thanks again, Ian
 >
 >
 >
 >
 > On 10/3/05, *Ingimar Robertsson* <iar at skyrr.is <mailto:iar at skyrr.is>>
 > wrote:
 >
 >     You could also check what environment variables the perl and shell
 >     scripts
 >     depend upon.  Perhaps they are missing in the cron environment (Cron
 >     jobs
 >     don't get the whole shell environment, which might explain why it
 >     does work
 >     from the shell)
 >
 >
 >     On Mon, Oct 03, 2005 at 07:39:48AM -0400, Mark Belanger wrote:
 >      > Ian mu wrote:
 >      > > Basically I have a perl script that runs once, first thing every
 >      > > morning, gathering some stats (currently turned off due to
 >     problem).
 >      > > Crontab -l shows the following...
 >      > >
 >      > > 00 6  * * * nice /home/statsman/stats/run_stats.sh  >/dev/null
 >     2>&1 (.sh
 >      > > file basically sources with full path a config with some vars,
 >     then runs
 >      > > the perl script).
 >      >
 >      > The first thing I would do to put some echos in run_stats.sh
 >      > and change > /dev/null to > /path/somefile
 >      >
 >      > If you're getting as far as the perl script, put some print
 >      > statements in it.
 >      >
 >      > You might try doing an strace from cron:
 >      >
 >      > 00 6  * * * strace -f -oOutputFile /home/statsman/stats/run_stats.sh
 >      > >/path/somefile 2>&1
 >      >
 >      > -Mark
 >      >
 >      > _______________________________________________
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 >      > CentOS at centos.org <mailto:CentOS at centos.org>
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 >
 >
 >     Bestu kveðjur,
 >
 >     Ingimar
 >
 >     --
 >     Ingimar Róbertsson, kerfisstjóri, RHCE          EMAIL: iar at skyrr.is
 >     <mailto:iar at skyrr.is>
 >     Skýrr hf                                        TEL:   +354-5695100
 >     Ármúli 2, 108 Reykjavík                         FAX:   +354-5695251
 >                http://www.skyrr.is/legal/disclaimer.txt
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 >
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-- 
Mark Belanger
LTX Corporation