Enabling automatic updates installation as they come available is quite easy.
First, install the yum-cron utility as followed :
yum install yum-cron
Make sure the service is running :
service yum-cron start
Then enable the service on boot :
chkconfig yum-cron on
Optionnaly, you may want to exclude some packages from being updated, just edit :
And append the following line (this example assume you want to exclude the kernel from being updated) :
NOTE : It may not be suitable for all servers or workstation to blindly install updates on their own, there are some cases you may prefer doing them manually after reviewing the list before applying them!