Although CentOS 6.x Instructions will work for CentOS 7.0, you could upgrade the installation process to be completely CentOS 7.0 compatible:
yum install yum-cron
systemctl disable yum-cron.service
systemctl stop yum-cron.service
.conf file (Configuration) located at: /etc/yum/yum-cron.conf AND /etc/yum/yum-cron-hourly.conf.
Note that in contrast to CentOS 6.x, by default yum-cron only download updates once a day and doesn’t apply them. change to:
apply_updates = yes
In /etc/yum/yum-cron.conf if you wish to. make note that you can now define hourly updates in the /etc/yum/yum-cron-hourly.conf file.