Centos6.5 python升级成2.7版本出现的一些问题解决方法

由于功能及程序依赖，需要将Centos上的python从2.6升级成2.7，把碰到的一些问题记录如下：

安装好2.7后将原来的/usr/bin/python改成/usr/bin/python26，并将2.7的bin目录加入执行路径

Question1： 执行yum报No module named yum

[root@zejin240 ~]# yum list
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:
2.7.12 (default, Jul  6 2016, 18:40:00)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-17)]

If you cannot solve this problem yourself, please go to
the yum faq at: http://yum.baseurl.org/wiki/Faq[/code] 
解决方法：

vi /usr/binyum

#!/usr/bin/python26

Question2: 执行pip时提示  ImportError: No module named pip

解决方法：python -m  ensurepip

Questions3:源码安装paramiko出现各种模块找不到

解决方法：

pip install -I pycrypto
pip install -I paramiko