1、首先备份系统自带yum源配置文件/etc/yum.repos.d/CentOS-Base.repo
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
2、下载ailiyun的yum源配置文件到/etc/yum.repos.d/
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
如果没联网的话,把这个文件复制到同地址目录一样
3、运行yum makecache生成缓存
yum makecache
4、这时候再更新系统就会看到以下mirrors.aliyun.com信息
[root@localhost ~]# yum -y update
已加载插件:fastestmirror, refresh-packagekit, security
设置更新进程Loading mirror speeds from cached hostfile
* base: mirrors.aliyun.com
* extras: mirrors.aliyun.com
* updates: mirrors.aliyun.com