终于解决了困扰了我一晚上的问题，在此感谢作者。原贴链接：http://blog.csdn.net/qq_36357820/article/details/77732656
下载了阿里和163的centos5.x的源，yum makecache的时候报错
[root@localhost yum.repos.d]# yum makecache
Loaded plugins: fastestmirror, security
Determining fastest mirrors
* addons: mirrors.aliyun.com
* base: mirrors.aliyun.com
* extras: mirrors.aliyun.com
* updates: mirrors.aliyun.com
http://mirrors.aliyun.com/centos/5/addons/x86_64/repodata/repomd.xml: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
http://mirrors.aliyuncs.com/centos/5/addons/x86_64/repodata/repomd.xml: [Errno 4] IOError: <urlopen error (111, '\xe6\x8b\x92\xe7\xbb\x9d\xe8\xbf\x9e\xe6\x8e\xa5')>
Trying other mirror.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: addons. Please verify its path and try again最终找到解决办法 ：
将之前的CentOS-Base.repo文件里的内容换成如下内容
vi /etc/yum.repos.d/CentOS-Base.repo
# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client. You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the
# remarked out baseurl= line instead.
#
#
[base]
name=CentOS-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/
baseurl=http://vault.centos.org/5.11/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5
#released updates
[updates]
name=CentOS-$releasever - Updates
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
#baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch/
baseurl=http://vault.centos.org/5.11/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
#baseurl=http://mirror.centos.org/centos/$releasever/extras/$basearch/
baseurl=http://vault.centos.org/5.11/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
#baseurl=http://mirror.centos.org/centos/$releasever/centosplus/$basearch/
baseurl=http://vault.centos.org/5.11/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5
#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib
#baseurl=http://mirror.centos.org/centos/$releasever/contrib/$basearch/
baseurl=http://vault.centos.org/5.11/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5</span></strong></span>
#yum makecache
#yum list