1、检查yum是否安装

rpm -qa |grep yum

2、利用CentOS的yum更新源来实现RHEL5的YUM功能

vi /etc/yum.repos.d/CentOS-Base.repo

[base]name=CentOS-5-Base#mirrorlist=http://mirrorlist.centos.org/?release=$releasever5&arch=$basearch&repo=os#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/baseurl=http://ftp.sjtu.edu.cn/centos/5/os/$basearch/gpgcheck=0gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5#released updates[update]name=CentOS-5-Updates#mirrorlist=http://mirrorlist.centos.org/?release=4&arch=$basearch&repo=updatesbaseurl=http://ftp.sjtu.edu.cn/centos/5/updates/$basearch/gpgcheck=0gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5#packages used/produced in the build but not released[addons]name=CentOS-5-Addons#mirrorlist=http://mirrorlist.centos.org/?release=4&arch=$basearch&repo=addonsbaseurl=http://ftp.sjtu.edu.cn/centos/5/addons/$basearch/gpgcheck=0gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5#additional packages that may be useful[extras]name=CentOS-5-Extras#mirrorlist=http://mirrorlist.centos.org/?release=4&arch=$basearch&repo=extrasbaseurl=http://ftp.sjtu.edu.cn/centos/5/extras/$basearch/gpgcheck=0gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5#additional packages that extend functionality of existing packages[centosplus]name=CentOS-5-Plus#mirrorlist=http://mirrorlist.centos.org/?release=4&arch=$basearch&repo=centosplusbaseurl=http://ftp.sjtu.edu.cn/centos/5/centosplus/$basearch/gpgcheck=0enabled=0gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5#contrib - packages by Centos Users[contrib]name=CentOS-5-Contrib#mirrorlist=http://mirrorlist.centos.org/?release=4&arch=$basearch&repo=contribbaseurl=http://ftp.sjtu.edu.cn/centos/5/contrib/$basearch/gpgcheck=0enabled=0gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5# vi dag.repo[dag]name=Dag RPM Repository for RHEL5baseurl=http://ftp.riken.jp/Linux/dag/redhat/el5/en/$basearch/dag/enabled=1gpgcheck=0gpgkey=http://ftp.riken.jp/Linux/dag/packages/RPM-GPG-KEY.dag.txt

3、导入key

rpm --import 

4、运行YUM，测试