遇到2个问题

1. 提示No module named yum ##因为yum版本不兼容需要重新安装

2. /usr/lib/python2.4/site-packages/_sqlitecache.so: wrong ELF class: ELFCLASS32 ##因为python版本问题，

   1.解决，重装yum

   2.解决，设置vim /usr/bin/yum  将注释##!/usr/bin/python2.4

附加重装方法 重装前一定确认系统版本是 i386 还是x64切记，要不还是会提错误

首先需要确定系统

#uname -a

Linux skw 2.6.18-164.el5 #1 SMP Tue Aug 18 15:51:48 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux

确认是x86_64之后，在网易的mirrors下载需要的rpm包：

http://mirrors.163.com/centos/5/os/x86_64/CentOS/

wget http://mirrors.163.com/centos/5/os/x86_64/CentOS/m2crypto-0.16-8.el5.x86_64.rpm

wget http://mirrors.163.com/centos/5/os/x86_64/CentOS/python-elementtree-1.2.6-5.x86_64.rpm

wget http://mirrors.163.com/centos/5/os/x86_64/CentOS/python-iniparse-0.2.3-4.el5.noarch.rpm

wget http://mirrors.163.com/centos/5/os/x86_64/CentOS/python-sqlite-1.1.7-1.2.1.x86_64.rpm

wget http://mirrors.163.com/centos/5/os/x86_64/CentOS/python-urlgrabber-3.1.0-6.el5.noarch.rpm

wget http://mirrors.163.com/centos/5/os/x86_64/CentOS/yum-3.2.22-39.el5.centos.noarch.rpm

wget http://mirrors.163.com/centos/5/os/x86_64/CentOS/yum-fastestmirror-1.1.16-21.el5.centos.noarch.rpm

wget http://mirrors.163.com/centos/5/os/x86_64/CentOS/yum-metadata-parser-1.1.2-3.el5.centos.x86_64.rpm

然后 安装软件包，并导入证书

1：删除自带的yum源

[root@localhost ~]# rpm -aq|grep yum|xargs rpm -e --nodeps

或者更新 下载的rpm

[root@localhost ~]# rpm -Uvh *

[root@localhost ~]# rpm -import http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-5

让yum使用网易的源：

#cd /etc/yum.repos.d/

#wget http://mirrors.163.com/.help/CentOS-Base-163.repo

编辑CentOS-Base-163.repo，在所有mirrorlist前面加上#，把所有$releasever替换成5，然后保存。

#yum clean metadata

#yum makecache

完成后yum可以正常工作，更新yum

#yum -y upgrade