安装编译相关工具
yum -y groupinstall "Development tools"
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
yum install libffi-devel -y
下载python安装包
wget https://www.python.org/ftp/python/3.8.3/Python-3.8.3.tgz
tar -zxvf Python-3.8.3.tgz
编译安装python
mkdir /usr/local/python3 #创建编译安装目录
cd Python-3.8.3
./configure --prefix=/usr/local/python3
make && make install
安装过，出现下面两行就成功了
Installing collected packages: setuptools, pip
Successfully installed pip-19.2.3 setuptools-41.2.0
创建软连接
# 查看当前python软连接
ll /usr/bin/ |grep python
lrwxrwxrwx 1 root root 7 Nov 26 2018 python -> python2
lrwxrwxrwx 1 root root 9 Nov 26 2018 python2 -> python2.7
-rwxr-xr-x 1 root root 7216 Jul 13 2018 python2.7
默认系统安装的是python2.7
删除python软连接
rm -rf /usr/bin/python
配置软连接为python3
#添加python3的软链接
ln -s /usr/local/python3/bin/python3 /usr/bin/python
这个时候看下python默认版本
python -V
删除默认pip软连接，并添加pip3新的软连接
rm -rf /usr/bin/pip
#添加 pip3 的软链接
ln -s /usr/local/python3/bin/pip3 /usr/bin/pip
更改yum配置
因为其要用到python2才能执行，否则会导致yum不能正常使用（不管安装 python3的那个版本，都必须要做的）
vi /usr/bin/yum
把 #! /usr/bin/python 修改为 #! /usr/bin/python2
vi /usr/libexec/urlgrabber-ext-down
把 #! /usr/bin/python 修改为 #! /usr/bin/python2
vi /usr/bin/yum-config-manager
#!/usr/bin/python 改为 #!/usr/bin/python2
