1.挂载光盘
#mount /dev/cdrom /media
2.删除/etc/yum.repos.d/目录下无用的repo文件
3.修改/etc/yum.repos.d/CentOS-Media.repo文件
[c6-media]
name=CentOS-$releasever - Media
baseurl=file:///media/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
4.执行yum clean all
5.执行yum list查看yum服务器是否工作