一、前言

升級glibc的時候根據INSTALL升級說明，要求python版本3.4以上。所以需要對python版本進行升級。centos7默認安裝的python版本為2.7.5，python通過yum安裝也只能安裝2.7.5版本，python3可以通過yum安裝3.6.8版本。如果需要更高的版本，只能通過源碼編譯安裝。此博文介紹源碼安裝方式升級python和python3版本，源碼編譯安裝要求操作系統已經安裝了gcc。環境說明如下：

• 操作系統：centos7.6
• python版本：升級前版本2.7.5，升級後2.7.18
• python3版本：升級前3.6.8，升級後版本3.8.8

二、python安裝步驟

1、查看當前python版本

[[email protected] ~]# python -V
Python 2.7.5

2、yum安裝python

[[email protected] ~]# yum install -y python2
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: mirrors.aliyun.com
* extras: mirrors.aliyun.com
* updates: mirrors.aliyun.com
Package python-2.7.5-90.el7.x86_64 already installed and latest version
Nothing to do

3、yum安裝python3

[[email protected] ~]# yum install -y python3
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Installed:
python3.x86_64 0:3.6.8-18.el7

Dependency Installed:
libtirpc.x86_64 0:0.2.4-0.16.el7 python3-libs.x86_64 0:3.6.8-18.el7 python3-pip.noarch 0:9.0.3-8.el7 python3-setuptools.noarch 0:39.2.0-10.el7

Complete!

三、python2升級步驟

0、查找需要升級的版本

python官網（包括python和python3所有的版本）查找需要安裝或者升級的版本。

1、下載python新版本

[[email protected] opt]# wget https://www.python.org/ftp/python/2.7.18/Python-2.7.18.tgz

2、解壓軟件包

[[email protected] opt]# tar -zxvf Python-2.7.18.tgz

3、預編譯軟件包

[[email protected] opt]# cd Python-2.7.18
[[email protected] Python-2.7.18]# ./configure --prefix=/usr

4、編譯軟件包

[[email protected] Python-2.7.18]# make
…
running build_scripts
creating build/scripts-2.7
copying and adjusting /opt/Python-2.7.18/Tools/scripts/pydoc -> build/scripts-2.7
copying and adjusting /opt/Python-2.7.18/Tools/scripts/idle -> build/scripts-2.7
copying and adjusting /opt/Python-2.7.18/Tools/scripts/2to3 -> build/scripts-2.7
copying and adjusting /opt/Python-2.7.18/Lib/smtpd.py -> build/scripts-2.7
changing mode of build/scripts-2.7/pydoc from 644 to 755
changing mode of build/scripts-2.7/idle from 644 to 755
changing mode of build/scripts-2.7/2to3 from 644 to 755
changing mode of build/scripts-2.7/smtpd.py from 644 to 755
/usr/bin/install -c -m 644 ./Tools/gdb/libpython.py python-gdb.py

5、安裝軟件包

[[email protected] Python-2.7.18]# make install

6、檢查升級後的版本

[[email protected] Python-2.7.18]# python -V
Python 2.7.18

四、python3升級步驟

1、下載安裝包

[[email protected] opt]# wget https://www.python.org/ftp/python/3.8.8/Python-3.8.8.tgz

2、解壓軟件包

[[email protected] opt]# tar -zxvf Python-3.8.8.tgz

3、預編譯

注意在編譯結束後會有提示"If you want a release build with all stable optimizations active (PGO, etc),please run ./configure --enable-optimizations"，加上–enable-optimizations預編譯的話後續編譯會報錯“Could not import runpy module ”，原因是gcc版本太低，enable-optimizations參數要求gcc版本8.1.0以上。

[[email protected] opt]# cd Python-3.8.8
[[email protected] Python-3.8.8]# ./configure

4、編譯

[[email protected] Python-3.8.8]# make
…
if test `uname -s` = Darwin; then
cp python-config.py python-config;
fi

5、編譯安裝

[[email protected] Python-3.8.8]# make install
…
Collecting setuptools
Collecting pip
Installing collected packages: setuptools, pip
Successfully installed pip-18.1 setuptools-40.6.2

6、升級後版本檢查

[[email protected] Python-3.6.10]# python3 -V
Python 3.8.8

五、QA

1、安裝python3.8.8的時候報錯zlib not available

• 報錯信息：zipimport.ZipImportError: can’t decompress data; zlib not available
• 報錯原因：沒有安裝zlib模塊
• 解決方案：安裝zlib模塊
  [[email protected] bin]# yum install -y zlib*

2、安裝完python之後yum報錯File “/usr/bin/yum”, line 30

• 報錯信息：File “/usr/bin/yum”, line 30
  
• 報錯原因：python軟連接指向了python3版本，而yum要求python2版本。
• 解決方案1：修改python命令軟連接到python2
  [[email protected] bin]# sln python2 python
  [[email protected] bin]# python -V
  Python 2.7.5
• 解決方案2：修改/usr/bin/yum文件，將python改為python2
  

3、安裝完成python之後yum安裝報錯File “/usr/libexec/urlgrabber-ext-down”, line 28

• 報錯信息：File “/usr/libexec/urlgrabber-ext-down”, line 28
• 報錯原因：yum下載程序依賴python2
• 解決方案1：修改python命令軟連接到python2
• 解決方案2：修改/usr/libexec/urlgrabber-ext-down文件，將python改為python2
  

4、升級到python2.7.18後報錯No module named rpm

• 報錯信息：There was a problem importing one of the Python modules required to run yum. The error leading to this problem was:
  No module named rpm
  
• 報錯原因：python2.7.18是python2的最新版本，已經移除了對yum的支持，centos8默認使用dnf軟件包安裝工具。
• 解決方案：從其他centos7服務器拷貝一個python2.7.5到服務器/usr/bin目錄下，然後重建python軟鏈接。