Centos7默认自带的python版本为2.7.5，但是很多软件都基于python3开发的，所以升级python3还是有必要的。

查看和备份python2.7.5

[root@test ~]# python -V
Python 2.7.5


###查看软连接指向
[root@test ~]# ls -al /usr/bin/python
lrwxrwxrwx 1 root root 7 May 19 19:39 /usr/bin/python -> python2

### 重命名软连接
mv /usr/bin/python /usr/bin/python2.7.5

升级前安装依赖软件：

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 libffi-devel

下载和编译安装python3.7.3

cd /use/local/src
wget https://www.python.org/ftp/python/3.7.3/Python-3.7.3.tar.xz

tar xf Python-3.7.3.tar.xz

cd Python-3.7.3

./configure
make
make install

编辑一下 yum 的配置文件，应用yum使用python 2.7.5

[root@vps219074 Python-3.7.3]# vi /usr/bin/yum

#!/usr/bin/python
修改为
#!/usr/bin/python2.7.5

[root@vps219074 Python-3.7.3]# vi /usr/libexec/urlgrabber-ext-down
#!/usr/bin/python
修改为
#!/usr/bin/python2.7.5

建立新的链接

rm -rf /usr/bin/python
rm -rf /usr/bin/py
ln -s /usr/local/bin/python3.7  /usr/bin/python

验证python是都升级成功，重新生成yum缓存

yum clean all
yum makecache

#python -V
Python 3.7.3