升级python，安装pip，Djang

Centos6.6 系统默认python版本是Python2.6.6.目前这个版本算很低了，主流是使用python2.7或者python3.0了；python2.6.6仅可以支持到Django1.3.7，这个DjanGo版本也太低了，很多特性不可使用，现在就升级到python2.6.6到python2.7.9，然后安装pip，通过pip安装Django的高版本！

1. 下载python2.7.9
# wget https://www.python.org/ftp/python/2.7.9/Python-2.7.9.tar.xz

2. 解压文件
tar xvf Python-2.7.9.tar.bz2

3. 创建安装目录
mkdir /usr/local/python27

4. 安装python
./configure --prefix=/usr/local/python27
make
make install

5. 修改老版本的ln指向（注意：这里修改后，可能会影响yum的使用）
[root@centos pip-1.5.6]# mv /usr/bin/python /usr/bin/python2.6.6

[root@centos pip-1.5.6]# ln -s /usr/local/python27/bin/python /usr/bin/python

报错：

[root@centos pip-1.5.6]# yum clean all

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:

2.7.9 (default, Dec 17 2014, 16:50:28)

[GCC 4.4.7 20120313 (Red Hat 4.4.7-11)]

If you cannot solve this problem yourself, please go to

the yum faq at:

Http://yum.baseurl.org/wiki/Faq

错误原因：错误信息描述为yum 所依赖的python不相符，请安装相对应的python即可

[root@centos pip-1.5.6]# rpm -qa | grep yum

yum-metadata-parser-1.1.2-16.el6.x86_64

yum-plugin-fastestmirror-1.1.30-30.el6.noarch

PackageKit-yum-0.5.8-23.el6.x86_64

yum-3.2.29-60.el6.centos.noarch

yum-plugin-security-1.1.30-30.el6.noarch

PackageKit-yum-plugin-0.5.8-23.el6.x86_64

yum-utils-1.1.30-30.el6.noarch

You have new mail in /var/spool/mail/root

[root@centos pip-1.5.6]# whereis python

python: /usr/bin/python2.6 /usr/bin/python /usr/lib/python2.6 /usr/lib64/python2.6 /usr/include/python2.6 /usr/share/man/man1/python.1.gz

[root@centos pip-1.5.6]# python -V

Python 2.7.9

现在系统上有两个版本的python！！！yum是由python写的！

一个是我刚安装的2.7.9,一个是centos默认安装的2.6.6

但是我执行了：

[root@centos pip-1.5.6]# mv /usr/bin/python /usr/bin/python2.6.6

[root@centos pip-1.5.6]# ln -s /usr/local/python27/bin/python /usr/bin/python

[root@centos Downloads]# python -V

Python 2.7.9

[root@centos pip-1.5.6]# which yum

/usr/bin/yum     这个文件使用了python，看来这个yum不支持，2.7.9高版本的python

解决：

[root@centos pip-1.5.6]# vim /usr/bin/yum

把python环境改成python2.6.6

pip：python软件包管理工具

参考：

安装之前：先安装openssl openssl-devel,后面你就会知道

https://pip.pypa.io/en/latest/installing.html

pip使用文档：

https://pypi.python.org/pypi/pip#downloads

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安装setuptools和pip  :

安装setuptools：

使用 ez_setup.py脚本安装setuptools

wget http://peak.telecommUnity.com/dist/ez_setup.py 
python ez_setup.py   

参考：什么是easy_install:

http://www.cnblogs.com/huangjacky/arcHive/2012/03/28/2421866.html

安装pip-1.4：后面讲如何升级pip

wget https://pypi.python.org/packages/source/p/pip/pip-1.4.tar.gz#md5=ca790be30004937987767eac42cfa44a 

tar -zxf pip-1.4.tar.gz && cd pip-1.4 
python setup.py install

PS. 记得设置%PYTHON_HOME%/Scripts/到PATH环境变量

#vim /etc/profile

  export PATH="/usr/local/Mysql/bin:/usr/local/python2.7/bin:$PATH"

#source /etc/profile

参考：pip的安装：

http://blog.csdn.net/cnyyx/article/details/25614669

参考：pip的用法

http://www.111cn.net/sys/linux/60630.htm

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#pip list --outdated

发现pip是pip-1.4版本太低可以更新：

将pip-1.4升级到pip-1.5.6：

# pip install --upgrade pip

报错：ImportError: cannot import name HTTPSHandler

[root@centos pip-1.5.6]# pip

Traceback (most recent call last):

File "/usr/bin/pip", line 9, in <module>

load_entry_point('pip==1.5.6', 'console_scripts', 'pip')()

File "build/bdist.linux-x86_64/egg/pkg_resources.py", line 458, in load_entry_point

File "build/bdist.linux-x86_64/egg/pkg_resources.py", line 2545, in load_entry_point

File "build/bdist.linux-x86_64/egg/pkg_resources.py", line 2244, in load

File "/usr/local/python27/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/__init__.py", line 10, in <module>

from pip.util import get_installed_distributions, get_prog

File "/usr/local/python27/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/util.py", line 18, in <module>

from pip._vendor.distlib import version

File "/usr/local/python27/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/_vendor/distlib/version.py", line 14, in <module>

from .compat import string_types

File "/usr/local/python27/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/_vendor/distlib/compat.py", line 31, in <module>

from urllib2 import (Request, urlopen, URLError, HTTPError,

ImportError: cannot import name HTTPSHandler

解决：安装openssl openssl-devel

解决：

yum install -y openssl   openssl-devel

然后重新编译python！！

安装Django：版本：1.7.1

[root@centos Downloads]# pip install Django

Downloading/unpacking Django

Downloading Django-1.7.1-py2.py3-none-any.whl (7.4MB):  20%  1.5MB

但是，悲剧的是：

python升级之后，KVM的图形管理界面就打不开了，但是KVM虚拟机都没有挂掉，只是说，图形管理界面挂了！！！

报错：

[root@centos ~]# virt-manager

Traceback (most recent call last):

File "/usr/share/virt-manager/virt-manager.py", line 400, in <module>

main()

File "/usr/share/virt-manager/virt-manager.py", line 251, in main

from virtManager import cli

File "/usr/share/virt-manager/virtManager/cli.py", line 29, in <module>

import libvirt

ImportError: No module named libvirt

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解决:

[root@centos ~]# /usr/bin/python2.6.6 -V

Python 2.6.6

[root@centos ~]# /usr/bin/python2.7 -V

Python 2.7.9

使用python2.6.6启动virt-manager :

[root@centos ~]# /usr/bin/python2.6.6 "/usr/share/virt-manager/virt-manager.py"