1、备份
[root@localhost ~]# yum -y install wget
[root@localhost ~]# mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
2、下载新的CentOS-Base.repo 到/etc/yum.repos.d/
3、添加EPEL
4、清理缓存并生成新的缓存
[root@localhost ~]# yum clean all
[root@localhost ~]# yum makecache
centos7更换阿里云yum源
原文:https://www.cnblogs.com/Bathing/p/15188421.html