每次都要百度一番，还不如自己做个记录，简单粗暴，哈哈哈哈
cd /etc/yum.repos.d mv CentOS-Base.repo CentOS-Base.repo.old wget http://mirrors.aliyun.com/repo/Centos-7.repo mv Centos-7.repo CentOS-Base.repo yum clean all yum makecache
原文：https://www.cnblogs.com/lemon-le/p/9151988.html