yum install -y wget
cd /etc/yum.repos.d/
mkdir backup
mv C* backup/
wget -O /etc/yum.repos.d/CenOS-Base.repo https://mirrors.aliyun.com/repo/Centos-7.repo
yum clean all
yum makecache
yum update -y
Centos 7 修改YUM镜像源地址为阿里云镜像地址
原文：https://www.cnblogs.com/jockming/p/12221886.html
