python升级后使用yum出现问题
[root@goolen ~]# python --version
Python 2.7.2

[root@goolen ~]# yum -y install python-devel
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 27 2015, 18:24:01) 
[GCC 4.4.6 20120305 (Red Hat 4.4.6-4)]

If you cannot solve this problem yourself, please go to 
the yum faq at:
  http://yum.baseurl.org/wiki/Faq

修改如下：
[root@goolen ~]# vim /usr/bin/yum           
#!/usr/bin/python_old        +++文件第一行，使用老的python版本

[root@goolen ~]# yum -y install python-devel
Loaded plugins: product-id, security, subscription-manager
Updating certificate-based repositories.
Unable to read consumer identity
local                                                                                                    | 4.0 kB     00:00 ... 
Setting up Install Process
Package python-devel-2.6.6-29.el6_2.2.x86_64 already installed and latest version
Nothing to do