cron job not executed

If you find your corn job doesn't executed and your crontab line is correct after careful check, it might be crond problem.

1. check if crond is running
ps -ef |grep crond
if crond is not running, start it.
service crond start

2. check log ( you must be root)
cat /var/log/cron
if you find error like below:
pam_access(crond:account): access denied for user `someuser' from `cron'
crond[9985]: CRON (someuser) ERROR: failed to open PAM security session: Success
crond[9985]: CRON (someuser) ERROR: cannot set security context
2.a check /etc/cron.allow and /etc/cron.deny
make sure user is allowed if cron.allow file exits
or not denied if cron.allow file doesn't exits.
2.b check /etc/security/access.conf
add +:ALL:cron crond

reference:
http://mochabomb.com/blog/cron-errors-crons-not-running-etc-centos-52/
http://www.flagword.net/2009/09/failed-to-open-pam-security-session/
http://www.linuxquestions.org/questions/linux-enterprise-47/cron-jobs-not-running-498478/