1. 安装nginx，createrepo
yum install nginx -y
yum install createrepo -y
2. 修改nginx配置文件,/etc/nginx/nginx.conf
location / {
autoindex on;
}
重启nginx, systemctl restart nginx
3. 在nginx根目录建立文件夹
mkdir -p /usr/share/nginx/html/CentOS_72_1511_Yum/Aliyun/version_7.2/64bit
4. 准备同步阿里云的源，base，updates，extras，epel, 确保/etc/yum.repos.d/ 下只有下面这两个repo
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo wget -O /etc/yum.repos.d/CentOS-epel.repo http://mirrors.aliyun.com/repo/epel-7.repo
5. 开始同步下载包
reposync -p /usr/share/nginx/html/CentOS_72_1511_Yum/Aliyun/version_7.2/64bit/
6. 建仓
createrepo -p /usr/share/nginx/html/CentOS_72_1511_Yum/Aliyun/version_7.2/64bit/base/Packages
createrepo -p /usr/share/nginx/html/CentOS_72_1511_Yum/Aliyun/version_7.2/64bit/extras/Packages
createrepo -p /usr/share/nginx/html/CentOS_72_1511_Yum/Aliyun/version_7.2/64bit/updates/Packages
createrepo -p /usr/share/nginx/html/CentOS_72_1511_Yum/Aliyun/version_7.2/64bit/epel
7. crontab定时同步
crontab -e
1 2 * * * /usr/bin/reposync -np /usr/share/nginx/html/CentOS_72_1511_Yum/Aliyun/version_7.2/64bit/
参考自：
http://blog.csdn.net/u012402276/article/details/53158682