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Too many cron jobs and crond processes running

February 17th, 2012 No comments

I faced a problem that a ton of crond processes(cronjobs, or crontab) were running on the OS:

root@localhost# ps auxww|grep cron
vare 543 0.0 0.0 141148 5904 ? S 01:43 0:00 crond
root 4085 0.0 0.0 72944 976 ? Ss 2010 1:13 crond
vare 4522 0.0 0.0 141148 5904 ? S Feb16 0:00 crond
vare 5446 0.0 0.0 141148 5904 ? S 02:43 0:00 crond
vare 9202 0.0 0.0 141148 5904 ? S Feb16 0:00 crond
vare 10245 0.0 0.0 141148 5908 ? S 03:43 0:00 crond
vare 13989 0.0 0.0 141148 5904 ? S Feb16 0:00 crond
vare 15487 0.0 0.0 141148 5908 ? S 04:43 0:00 crond
vare 18796 0.0 0.0 141148 5904 ? S Feb16 0:00 crond
vare 20448 0.0 0.0 141148 5908 ? S 05:43 0:00 crond
root 23168 0.0 0.0 6024 596 pts/0 S+ 06:15 0:00 grep cron
vare 23474 0.0 0.0 141148 5904 ? S Feb16 0:00 crond
vare 27183 0.0 0.0 141148 5904 ? S Feb16 0:00 crond
vare 28358 0.0 0.0 141148 5904 ? S 00:43 0:00 crond
vare 32032 0.0 0.0 141148 5904 ? S Feb16 0:00 crond

.....(and more)

Now let's see what cronjobs are running by user vare:
root@localhost# crontab -u vare -l
# run the VERA Deploy routine
43 * * * * cd /share/scripts > /dev/null 2>&1 ; sleep 5 ; /share/scripts/Application/VARE/Deploy > /dev/null 2>&1

After check the script /share/bbscripts/Application/VERA/Deploy, I can see that the script is changing directory to a NFS mount point<i.e. cd /share/scripts> and then do some checks<i.e. /share/scripts/Application/VARE/Deploy>. But as there's problem during the process it's changing to NFS mount point, so the script hung there and didn't quit normally. As such, the number of crond was increasing.

Method to solve this specific problem(specific means you've to check your own script) is to first kill the hung processes of crond, then bounce autofs and then restart crond.