1、下载python并解压

地址：https://www.python.org/ftp/python/

tar -zxvf Python-3.9.9.tgz

2、安装依赖包

yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel gcc libffi-devel gcc make automake autoconf libtool libffi-devel

yum -y groupinstall "Development tools"

yum install libffi-devel -y

3、创建安装目录

mkdir /usr/local/python3

4、安装python

cd Python-3.9.9

./configure --prefix=/usr/local/python3

make && make install

出现如下输出则代表安装成功

Installing collected packages: setuptools, pip

Successfully installed pip-21.1.1 setuptools-56.0.0

5、创建软连接

查看当前python软连接

ll /usr/bin/ |grep python

删除默认软链接，配置软连接为python3

rm -rf /usr/bin/python

ln -s /usr/local/python3/bin/python3 /usr/bin/python

查看是否更改成功

[root@localhost ~]# python -V
Python 3.9.9

删除默认pip软连接，并添加pip3新的软连接

rm -rf /usr/bin/pip

ln -s /usr/local/python3/bin/pip3 /usr/bin/pip

还可以配个pip3的

ln -s /usr/local/python3/bin/pip3.9 /usr/bin/pip3

验证

[root@localhost ~]# pip3 -V
pip 21.2.4 from /usr/local/python3/lib/python3.9/site-packages/pip (python 3.9)

6、更改yum配置

将如下配置文件的 #! /usr/bin/python 都修改为 #! /usr/bin/python2

vi /usr/bin/yum

vi /usr/libexec/urlgrabber-ext-down

vi /usr/bin/yum-config-manager //这个文件如果是空的话，就随便执行一个yum安装

7、最后就可以使用python3了