1、Centos升级后，pip时会报如下错误：

Traceback (most recent call last):
  File "./pip", line 5, in <module>
    from pkg_resources import load_entry_point
  File "/opt/soft/distribute-0.7.3/pkg_resources.py", line 2989, in <module>
    working_set.require(__requires__)
  File "/opt/soft/distribute-0.7.3/pkg_resources.py", line 726, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/opt/soft/distribute-0.7.3/pkg_resources.py", line 624, in resolve
    raise DistributionNotFound(req)
pkg_resources.DistributionNotFound: pip==1.5.5

是因为python升级后版本不对应的原因，需要重新安装pip。

2、

CentOS升级Python2.7后， yum出现“No module named yum”错误：

由于yum命令不兼容python2.7，需修改/usr/bin/yum文件，将第一行由“#!/usr/bin/python”改为“#!/usr/bin/python2.6"，而“#!/usr/bin/python”的软链接是python2.7。