1.首先来看一下系统版本
[root@python3 ~]# cat /etc/redhat-release
CentOS Linux release 7.6.1810 (Core)2.更新一下yum源，yum源我这里用的都是阿里云的源
[root@python3 ~]# cd /etc/yum.repos.d/
[root@python3 yum.repos.d]# mkdir bak
[root@python3 yum.repos.d]# mv * bak
[root@python3 yum.repos.d]# wget http://mirrors.aliyun.com/repo/Centos-7.repo
[root@python3 yum.repos.d]# wget http://mirrors.aliyun.com/repo/epel-7.repo