一.問題描述

執行py指令碼時，提示ImportError: No module named MySQLdb錯誤，如下：
[[email protected] sh]# python 1.py
Traceback (most recent call last):
File "1.py", line 4, in <module>
import MySQLdb
ImportError: No module named MySQLdb

版本：centOS 6.6

二.問題分析
先檢視當前python版本
[[email protected] sh]# python -V
Python 2.7.13
[

[email protected] sh]# python
Python 2.7.13 (default, Apr 11 2017, 17:58:38)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-11)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>

檢視OS安裝的python相關情況：
[[email protected] sh]# rpm -qa|grep python
.....
.....
MySQL-python-1.2.3-0.3.c1.1.el6.x86_64
python-2.6.6-52.el6.x86_64
......
就是說OS存在兩個python版本2.6.6和2.7.13，猜測與多個版本同時存在會引起上面報錯，所以嘗試刪除2.6.6版，先是刪除了MySQL-python，再刪除python,報錯如下：
yum remove python-2.6.6-52.el6.x86_64
........................
.........................
--> Running transaction check
---> Package redhat-lsb-compat.x86_64 0:4.0-7.el6.centos will be erased
--> Finished Dependency Resolution
Error: Trying to remove "yum", which is protected
提示yum有保護，不能移除，採用跳過相依賴包來直接刪除：rpm -e --nodeps python-2.6.6-52.el6.x86_64 成功，再安裝MySQL-python，卻提示如下：
[

[email protected] sh]# yum install MySQL-python
-bash: /usr/bin/yum: /usr/bin/python: bad interpreter: No such file or directory

檢視yum和python的rpm是否安裝，確認系統已安裝yum和python的的rpm包。
檢視一下系統命令：
#yum命令存在
[[email protected] sh]# ll /usr/bin/yum
-rwxr-xr-x. 1 root root 801 Oct 16 2014 /usr/bin/yum

[[email protected]

bin]# pwd
/usr/bin
[[email protected] bin]# ls -al|grep python
-rwxr-xr-x. 1 root root 11232 Oct 16 2014 abrt-action-analyze-python

原來python的軟連線原始檔已經不存在，所以出現上面錯誤：
重新做一個python的軟連線:
# ln -s /usr/local/python27/bin/python /usr/bin/python
由於yum只相容python 2.6，而不相容2.7，所以老版本還是要找回來，等於現在又要走回去，重頭再來。
cd /usr/local/src/
mkdir Python-2.6.6
cd /media/Packages （在os安裝盤中)
cp python-2.6.6-52.el6.x86_64.rpm /usr/local/src/Python-2.6.6/
cp python-urlgrabber-3.9.1-9.el6.noarch.rpm /usr/local/src/Python-2.6.6/
cp python-devel-2.6.6-52.el6.x86_64.rpm /usr/local/src/Python-2.6.6/
cp python-libs-2.6.6-52.el6.x86_64.rpm /usr/local/src/Python-2.6.6/
cp yum-3.2.29-60.el6.centos.noarch.rpm /usr/local/src/Python-2.6.6/
cd /usr/local/src/Python-2.6.6/
[[email protected] Python-2.6.6]# rpm -Uvh --replacepkgs *.rpm
warning: python-2.6.6-52.el6.x86_64.rpm: Header V3 RSA/SHA1 Signature, key ID c105b9de: NOKEY
Preparing... ########################################### [100%]
1:python-libs ########################################### [ 20%]
2:python ########################################### [ 40%]
3:python-urlgrabber ########################################### [ 60%]
4:yum ########################################### [ 80%]
5:python-devel ########################################### [100%]

更改yum的python版本：
vi /usr/bin/yum
#!/usr/bin/python改為#!/usr/bin/python-2.6.6
將python改名:
[[email protected] bin]# mv /usr/bin/python /usr/bin/python-2.6.6
[[email protected] bin]# ln -s /usr/local/python27/bin/python /usr/bin/python

再安裝：yum install MySQL-python 安裝成功！
[[email protected] sh]# rpm -qa|grep MySQL-python
MySQL-python-1.2.3-0.3.c1.1.el6.x86_64

執行py指令碼時，依然提示：ImportError: No module named MySQLdb錯誤，說明這個與有多個python版本同時存在沒有關係。

三.問題解決
懷疑是python版本與MySQL-python版本不一致引起，所以從網上下載python 2.7.13對應的MySQL-python-1.2.5進行安裝，如下：
[[email protected]>MySQL-python-1.2.5]# python setup.py build
Traceback (most recent call last):
File "setup.py", line 7, in <module>
import setuptools
ImportError: No module named setuptools
這次提示ImportError: No module named setuptools，說明沒有找到setuptools包，需要下載安裝：
wgethttp://pypi.python.org/packages/source/s/setuptools/setuptools-0.6c11.tar.gz
tar zxvf setuptools-0.6c11.tar.gz
cd setuptools-0.6c11
python setup.py build ----正常完成
python setup.py install ----正常完成
同時需要安裝：yum install python-devel。
[email protected] MySQL-python-1.2.5]# python setup.py build
sh: mysql_config: command not found
Traceback (most recent call last):
File "setup.py", line 17, in <module>
metadata, options = get_config()
File "/data/tool/MySQL-python-1.2.5/setup_posix.py", line 43, in get_config
libs = mysql_config("libs_r")
File "/data/tool/MySQL-python-1.2.5/setup_posix.py", line 25, in mysql_config
raise EnvironmentError("%s not found" % (mysql_config.path,))
EnvironmentError: mysql_config not foun
這次丟擲的錯誤與上面不同，從提示看，說明有個檔案屬性沒開啟，修改site.cfg，將mysql_config這個屬性開啟，如下：
[options]
# embedded: link against the embedded server library
# threadsafe: use the threadsafe client
# static: link against a static library (probably required for embedded)

embedded = False
threadsafe = True
static = False

# The path to mysql_config.
# Only use this if mysql_config is not on your PATH, or you have some weird
# setup that requires it.
mysql_config = /apps/svr/mariadb10/bin/mysql_config

注意以上mysql_config那行，與安裝的mysql目錄有關，自己去找自己安裝的mysql目錄即可。

[[email protected]  MySQL-python-1.2.5]# python setup.py build

running build
running build_py
creating build
......
成功完成.
[[email protected] MySQL-python-1.2.5]#python setup.py install
running install
running bdist_egg
running egg_info
..................
..................
Installed /usr/local/lib/python2.7/site-packages/MySQL_python-1.2.5-py2.7-linux-x86_64.egg
Processing dependencies for MySQL-python==1.2.5
Finished processing dependencies for MySQL-python==1.2.5
成功完成。
再執行py指令碼，這個不再提示No module named MySQLdb錯誤了，而是libmysqlclient.so.18檔案找不到
[[email protected] sh]# python 1.py
Traceback (most recent call last):
File "1.py", line 4, in <module>
import MySQLdb
File "build/bdist.linux-x86_64/egg/MySQLdb/__init__.py", line 19, in <module>
File "build/bdist.linux-x86_64/egg/_mysql.py", line 7, in <module>
File "build/bdist.linux-x86_64/egg/_mysql.py", line 6, in __bootstrap__
ImportError: libmysqlclient.so.18: cannot open shared object file: No such file or directory
修改/etc/profile檔案裡，新增如下內容：
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/apps/svr/mariadb10/lib:/usr/local/lib
並執行source /etc/profile
再執行python 1.py不再報錯。