Centos最小化安装时候貌似crond是不带的，需要自己手动安装。但是Centos不同的版本安装命令不一样，在此记录一下！

# On CentOS 7 you need to use cronie:

yum install -y cronie

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

yum install -y vixie-cron

# 启用

systemctl enable crond

systemctl restart crond

参考：

http://www.landui.com/questions/21802223/how-to-install-crontab-on-centos