O Centos usa o cronie e lê arquivos / crontabs dos seguintes locais:
/etc/cron.d/ # Put any readable file here. Syntax example in /etc/crontab
/etc/cron.daily/ # Any root executable files here. runs daily
/etc/cron.deny # newline separated list of users to deny crontab.
/etc/cron.hourly/ # Same setup as daily
/etc/cron.monthly/ # same setup as daily
/etc/crontab # Shell variables that all cron jobs source before running.
/etc/cron.weekly/ # same setup as daily
/var/spool/cron/* # most user defined cron jobs are put here.