ex. /media/CentOS* , /media/RHEL*
2. Create a symbolic link to /media/dvd_image
ln -s /media/CentOS /media/dvd_image
3. Edit /etc/yum.conf.d/dvd.repo , adding the following
[dvd] name=dvd baseurl=file:///media/dvd_image/Server enabled=1 gpgcheck=0
4. Update yum database
yum update
5. Install packages needed