yum install 在紅帽中提示”This system is not registered with RHN”的解決方案

第一步：卸載rhel的默認安裝的yum包
查看yum包
rpm  -qa|grep yum

卸載之
rpm  -qa|grep yum|xargs rpm -e --nodeps

第二步：下載新的yum包
打開網頁 http://mirrors.ustc.edu.cn/centos/5/os/i386/CentOS/
找到下列rpm包，下載並安裝
yum-3.2.22-26.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

並且安裝之
rpm -ivh yum-*

注意：yum和yum-fastestmirror相互依賴，所以同時安裝即可。

第三步：下載yum的配置源

wget   http://www.linuxidc.com/files/2011/05/06/CentOS-Base.repo

下載到 /etc/yum.repos.d/ 目錄下面

第四步：運行yum makecache生成緩存

[root@localhost yum.repos.d]# yum makecache

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:
2.7.2 (default, Mar 11 2012, 03:08:10)
[GCC 4.1.2 20080704 (Red Hat 4.1.2-46)]

If you cannot solve this problem yourself, please go to
the yum faq at:

  http://wiki.linux.duke.edu/YumFaq

我在做第四步的時候出現上面的錯誤，原因是我升級了python， 解決方法如下

[root@localhost yum.repos.d]# whereis python
python: /usr/bin/python /usr/bin/python2.4 /usr/lib/python1.5 /usr/lib/python2.4 /usr/local/bin/python2.7 /usr/local/bin/python2.7-config /usr/local/bin/python /usr/local/lib/python2.7 /usr/include/python2.4 /usr/share/man/man1/python.1.gz

[root@localhost yum.repos.d]# vi /usr/bin/yum

#!/usr/bin/python
import sys

把第一行修改為   #!/usr/bin/python2.4， 然後保存退出。

[root@localhost yum.repos.d]# yum makecache
Loaded plugins: fastestmirror
Determining fastest mirrors
addons                                                                                             | 1.9 kB     00:00    
addons/filelists_db                                                                                |  564 B     00:00    
addons/other_db                                                                                    |  552 B     00:00    
addons/primary_db                                                                                  | 1.1 kB     00:00    
base                                                                                               | 1.1 kB     00:00    
base/filelists                                                                                     | 3.0 MB     00:01    
這樣就成功了。