Setup yum repositories to install or update from local mounted iso file

First mount iso file
mount -o loop /path/to/isofile.iso /media/cdrom


Create dvd.repo in /etc/yum.repos.d


example dvd.repo

[dvd]
name=Red Hat Enterprise Linux 6.1
mediaid=1305068199.328169
metadata_expire=-1
gpgcheck=0
cost=500
baseurl=file:///media/cdrom/
enabled=1