用iso建立本地yum源
http://www.ibm.com/developerworks/cn/linux/l-cn-yum/index.html?ca=drs-
# mount -o loop rhel-server-5.4-i386-dvd.iso /media/cdrom
# cat > /etc/yum.repos.d/dvd.repo
[dvd] name=install dvd baseurl=file:///media/cdrom/Server enabled=1 gpgcheck=0
