升级后在运行yum出现问题
There was a problem importing one of the Python modules
required to run yum. The error leading to this problem was:
No module named yum
Please install a package which provides this module, or
verify that the module is installed correctly.
It's possible that the above module doesn't match the
current version of Python, which is:
2.6.1 (r261:67515, Aug 7 2010, 11:36:17)
[GCC 4.1.2 20080704 (Red Hat 4.1.2-44)]
If you cannot solve this problem yourself, please go to the yum faq at:
http://wiki.linux.duke.edu/YumFaq
提示当前版本是2.6.1可能版本不匹配。没有yum依赖的包。
头脑一热既然yum不兼容，则想着卸载yum重新安装。卸载yum是大忌在linux中。卸载后安装比较麻烦。yum完全安装需要：
yum-3.2.22-33.el5.centos.noarch.rpm
yum-fastestmirror-1.1.16-14.el5.centos.1.noarch.rpm
yum-metadata-parser-1.1.2-3.el5.centos.i386.rpm
在三个包在没有yum的情况下比较难找，好在在centos的安装文件中有安装如下：
mkdir /test/media #创建挂在目录
mnt /dev/dvd /test/media #挂在dvd
cd /test/media/centos
rpm -ivh yum-3.2.22-33.el5.centos.noarch.rpm
yum-fastestmirror-1.1.16-14.el5.centos.1.noarch.rpm
yum-metadata-parser-1.1.2-3.el5.centos.i386.rpm
由于升级了python,此时运行yum还是会报错，只需要修改yum配置文件让yum用旧版本的python运行即可：
vi /usr/bin/yum将 #!/usr/bin/python 改为: #!/usr/bin/python2.4
使用python 升级yum：
安装EPEL的rpm包 rpm -ivh http://download.slogra.com/epel-release-5-4.noarch.rpm yum升级python yum -y install python26 备份老的python版本,并使用新python版本 mv /usr/bin/python /usr/bin/python.old ln -s /usr/bin/python26 /usr/bin/python vi /usr/bin/yum 将第一行的python后加上2.4,即第一行改为: #!/usr/bin/python2.4
参考文章：
http://blog.slogra.com/post-235.html
http://blog.sina.com.cn/s/blog_62c8f3c901012s5c.html
http://blog.csdn.net/oyzl68/article/details/22932227
http://blog.chinaunix.net/uid-29020-id-3886291.html