备份本地的yum源配置文件

mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup

下载对应版本repo文件, 放入/etc/yum.repos.d

以centos7为例
cd /etc/yum.repos.d/ && wget http://mirrors.163.com/.help/CentOS7-Base-163.repo
mv CentOS7-Base-163.repo CentOS-Base.repo

生产缓存

yum clean all

参考网址:​​http://mirrors.163.com/.help/centos.html​