centos6有些商家镜像没有带crontab,需要的话要自己安装,但是centos6和centos5安装crontab是不一样的,因为变更了一些依赖关系。
crontab package in CentOS is vixie-cron.

yum install vixie-cron
service crond start
chkconfig crond on

 

On CentOs 6 you can still install vixie-cron, but the real package is cronie:

yum install vixie-cron
或者
yum install cronie

On CentOS 7 vixie-cron is not longer available, so you need to use cronie:

yum install cronie