* insert DVD/ISO to CD-ROM/DVD-ROM drive *
1. mount yum source iso to /mnt
--> mount /dev/xvdd /mnt
2. Create repository file
--> vi /etc/yum.repos.d/centos6.repo
[CentOS6-Repository] name=CentOS6 repository baseurl=file:///mnt enabled=1 gpgcheck=0
3. Deny yum from network, in /etc/yum.repos.d/
--> mv CentOS-Base.repo CentOS-Base.repo.bak
4. yum clean all
5. yum install xxxx
