如果没有wget，先安装一个。(如果有请蹦过)
yum install wget -y
备份本地yum源
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo_bak
获取阿里yum源配置文件
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
原文：https://www.cnblogs.com/dongqiliang/p/11921930.html