YUM是Redhat Linux在线安装更新及软件的工具，但是这是RHEL5的收费功能，如果没有购买Redhat的服务时不能使用RHEL5的更新源的，会提示注册。
由于CentOS是从Redhat演化而来的免费Linux版本，因此可以利用CentOS的yum更新源来实现RHEL5的YUM功能。配置方法如下：
检查yum是否安装，默认情况下都是安装好的，总共4各包。
[root@linux-a ~]# rpm -qa |grep yum
yum-metadata-parser-1.0-8.fc6
yum-3.0.1-5.el5
yum-rhn-plugin-0.4.3-1.el5
yum-updatesd-3.0.1-5.el5
2.下载并安装python-urlgrabber，python-pycurl，yum-metadata-parser
[root@akinlau?0?2~]wget http://tel.mirrors.163.com/centos/6/os/x86_64/Packages/python-urlgrabber-3.9.1-8.el6.noarch.rpm
[root@akinlau?0?2~]wget http://tel.mirrors.163.com/centos/6/os/x86_64/Packages/python-pycurl-7.19.0-8.el6.x86_64.rpm
[root@akinlau?0?2~]wget http://tel.mirrors.163.com/centos/6/os/x86_64/Packages/yum-metadata-parser-1.1.2-16.el6.x86_64.rpm
[root@akinlau?0?2~]rpm -ivh python-urlgrabber-3.9.1-8.el6.noarch.rpm python-pycurl-7.19.0-8.el6.x86_64.rpm yum-metadata-parser-1.1.2-16.el6.x86_64.rpm
注：如果不安装python-urlgrabber，python-pycurl，yum-metadata-parser这3个包的话，在下面运行http://www.360doc.cn/article/yummain.py install yum的话会报以下错误：
报错1：
[root@akinlau yum-3.4.3]# http://www.360doc.cn/article/yummain.py?0?2
Traceback (most recent call last):
File “http://www.360doc.cn/article/yummain.py”, line 28, in<module>
from yum import Errors
File “/root/nagios/yum-3.4.3/yum/__init__.py”, line 52, in<module>
import config
File “/root/nagios/yum-3.4.3/yum/config.py”, line 30, in<module>
from parser import ConfigPreProcessor, varReplace
File “/root/nagios/yum-3.4.3/yum/parser.py”, line 4, in<module>
import urlgrabber
ImportError:Nomodulenamedurlgrabber
报错2：
[root@akinlau yum-3.4.3]# http://www.360doc.cn/article/yummain.py?0?2
Traceback (most recent call last):
File “http://www.360doc.cn/article/yummain.py”, line 28, in<module>
from yum import Errors
File “/root/nagios/yum-3.4.3/yum/__init__.py”, line 55, in<module>
import rpmsack
File “/root/nagios/yum-3.4.3/yum/rpmsack.py”, line 38, in<module>
import yum.depsolve
File “/root/nagios/yum-3.4.3/yum/depsolve.py”, line 30, in<module>
from transactioninfo import TransactionMember
File “/root/nagios/yum-3.4.3/yum/transactioninfo.py”, line 32, in<module>
from sqlitesack import YumAvailablePackageSqlite
File “/root/nagios/yum-3.4.3/yum/sqlitesack.py”, line 26, in<module>
import yumRepo
File “/root/nagios/yum-3.4.3/yum/yumRepo.py”, line 33, in<module>
importsqlitecachec
ImportError:Nomodulenamedsqlitecachec
配置yum更新源
创建/etc/yum.repos.d/CentOS-Base.repo文件，定义yum更新源，这里使用的是上海交大的CentOS更新源
[root@linux-a ~]# 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/$basearch/
gpgcheck=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5
#released updates
[update]
name=CentOS-5-Updates
#mirrorlist=http://mirrorlist.centos.org/?release=4&arch=$basearch&repo=updates
baseurl=http://ftp.sjtu.edu.cn/centos/5/updates/$basearch/
gpgcheck=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5
#packages used/produced in the build but not released
[addons]
name=CentOS-5-Addons
#mirrorlist=http://mirrorlist.centos.org/?release=4&arch=$basearch&repo=addons
baseurl=http://ftp.sjtu.edu.cn/centos/5/addons/$basearch/
gpgcheck=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5
#additional packages that may be useful
[extras]
name=CentOS-5-Extras
#mirrorlist=http://mirrorlist.centos.org/?release=4&arch=$basearch&repo=extras
baseurl=http://ftp.sjtu.edu.cn/centos/5/extras/$basearch/
gpgcheck=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-5-Plus
#mirrorlist=http://mirrorlist.centos.org/?release=4&arch=$basearch&repo=centosplus
baseurl=http://ftp.sjtu.edu.cn/centos/5/centosplus/$basearch/
gpgcheck=0
enabled=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5
#contrib - packages by Centos Users
[contrib]
name=CentOS-5-Contrib
#mirrorlist=http://mirrorlist.centos.org/?release=4&arch=$basearch&repo=contrib
baseurl=http://ftp.sjtu.edu.cn/centos/5/contrib/$basearch/
gpgcheck=0
enabled=0
gpgkey=http://mirror.centos.org/centos/RPM-GPG-KEY-centos5
# vi dag.repo
[dag]
name=Dag RPM Repository for RHEL5
baseurl=http://ftp.riken.jp/Linux/dag/redhat/el5/en/$basearch/dag/
enabled=1
gpgcheck=0
gpgkey=http://ftp.riken.jp/Linux/dag/packages/RPM-GPG-KEY.dag.txt
导入key
[root@linux-a ~]# rpm --import http://ftp.sjtu.edu.cn/centos/5/os/i386/RPM-GPG-KEY-CentOS-5
运行YUM，测试
[root@linux-a ~]# yum install xmms-mp3
Loading "installonlyn" plugin
Loading "rhnplugin" plugin
This system is not registered with RHN.
RHN support will be disabled.
Setting up Install Process
Setting up repositories
Reading repository metadata in from local files
Parsing package install arguments
Resolving Dependencies
-->Populating transaction set with selected packages. Please wait.
--->Package xmms-mp3.i386 1:1.2.10-16.el5.rf set to be updated
-->Running transaction check
-->Processing Dependency: libglib-1.2.so.0 for package: xmms-mp3
-->Processing Dependency: libgdk-1.2.so.0 for package: xmms-mp3
-->Processing Dependency: libgthread-1.2.so.0 for package: xmms-mp3
-->Processing Dependency: libgmodule-1.2.so.0 for package: xmms-mp3
-->Processing Dependency: libgtk-1.2.so.0 for package: xmms-mp3
-->Processing Dependency: libxmms.so.1 for package: xmms-mp3
-->Restarting Dependency Resolution with new changes.
-->Populating transaction set with selected packages. Please wait.
--->Package xmms.i386 1:1.2.10-14.el5.rf set to be updated
--->Package glib.i386 1:1.2.10-20.el5 set to be updated
--->Downloading header for gtk+ to pack into transaction set.
gtk+-1.2.10-56.el5.i386.r 100% |=========================| 25 kB 00:00
--->Package gtk+.i386 1:1.2.10-56.el5 set to be updated
-->Running transaction check
-->Processing Dependency: libmikmod.so.2 for package: xmms
-->Processing Dependency: gdk-pixbuf >=0.18.0 for package: gtk+
-->Restarting Dependency Resolution with new changes.
-->Populating transaction set with selected packages. Please wait.
--->Downloading header for gdk-pixbuf to pack into transaction set.
gdk-pixbuf-0.22.0-25.el5. 100% |=========================| 16 kB 00:00
--->Package gdk-pixbuf.i386 1:0.22.0-25.el5 set to be updated
--->Downloading header for mikmod to pack into transaction set.
mikmod-3.1.6-38.1.i386.rp 100% |=========================| 7.7 kB 00:00
--->Package mikmod.i386 0:3.1.6-38.1 set to be updated
-->Running transaction check
Dependencies Resolved
=============================================================================
Package Arch Version Repository Size
=============================================================================
Installing:
xmms-mp3 i386 1:1.2.10-16.el5.rf dag 179 k
Installing for dependencies:
gdk-pixbuf i386 1:0.22.0-25.el5 base 231 k
glib i386 1:1.2.10-20.el5 base 137 k
gtk+ i386 1:1.2.10-56.el5 base 923 k
mikmod i386 3.1.6-38.1 base 201 k
xmms i386 1:1.2.10-14.el5.rf dag 2.3 M
Transaction Summary
=============================================================================
Install 6 Package(s)
Update 0 Package(s)
Remove 0 Package(s)
Total download size: 3.9 M
Is this ok [y/N]: