转摘：https://www.jianshu.com/p/45919a9dbd5b
在yum安装程序时有时会很慢或者直接超时中断，这种情况可以更改yum源为国内源。
修改CentOS默认yum源为mirrors.163.com
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、进入yum源配置文件所在的文件夹
cd /etc/yum.repos.d/
3、下载163的yum源配置文件到上面那个文件夹内
CentOS7
wget -O /etc/yum.repos.d/CentOS7-Base-163.repo http://mirrors.163.com/.help/CentOS7-Base-163.repo
CentOS6
wget -O /etc/yum.repos.d/CentOS6-Base-163.repo http://mirrors.163.com/.help/CentOS6-Base-163.repo
CentOS5
wget -O /etc/yum.repos.d/CentOS5-Base-163.repo http://mirrors.163.com/.help/CentOS5-Base-163.repo
4、运行yum makecache生成缓存
yum makecache
5、这时候再更新系统就会看到以下mirrors.163.com信息
yum -y update
修改CentOS默认yum源为mirrors.aliyun.com
步骤跟上面的一样只是下载源不一样
CentOS7
wget -O /etc/yum.repos.d/Centos-7.repo http://mirrors.aliyun.com/repo/Centos-7.repo
CentOS6
wget -O /etc/yum.repos.d/Centos-6.repo http://mirrors.aliyun.com/repo/Centos-6.repo
CentOS5
wget -O /etc/yum.repos.d/Centos-5.repo http://mirrors.aliyun.com/repo/Centos-5.repo
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yum源配置文件所在的文件夹
cd /etc/yum.repos.d/
mirrors.163.com
CentOS7
wget -O /etc/yum.repos.d/CentOS7-Base-163.repo http://down.wbvip.cn/huanjing/yum/CentOS7-Base-163.repo
CentOS6
wget -O /etc/yum.repos.d/CentOS6-Base-163.repo http://down.wbvip.cn/huanjing/yum/CentOS6-Base-163.repo
CentOS5
wget -O /etc/yum.repos.d/CentOS5-Base-163.repo http://down.wbvip.cn/huanjing/yum/CentOS5-Base-163.repo
mirrors.aliyun.com
CentOS7
wget -O /etc/yum.repos.d/Centos-7.repo http://down.wbvip.cn/huanjing/yum/Centos-7.repo
CentOS6
wget -O /etc/yum.repos.d/Centos-6.repo http://down.wbvip.cn/huanjing/yum/Centos-6.repo
CentOS5
wget -O /etc/yum.repos.d/Centos-5.repo http://down.wbvip.cn/huanjing/yum/Centos-5.repo