1. 备份原来的源
2. 拉取
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
或者
curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
3、更新镜像源
清除缓存：yum clean all
生成缓存：yum makecache
转载于:https://www.cnblogs.com/mu-zhang/p/11611516.html