进入到yum源配置文件所在的文件夹

[root@betty ~]# cd /etc/yum.repos.d/  

下载163

[root@betty yum.repos.d]# wget http://mirrors.163.com/.help/CentOS7-Base-163.repo

运行yum生成缓存

[root@betty yum.repos.d]# yum makecache  

更新系统

[root@betty yum.repos.d]# yum -y update

查看结果

···
Loading mirror speeds from cached hostfile  
 * base: mirrors.163.com  
 * extras: mirrors.163.com  
 * updates: mirrors.163.com  
···