所在地区可用的ISO下载地址：
http://mirrors.neusoft.edu.cn/centos/7.9.2009/isos/x86_64/
http://mirrors.aliyun.com/centos/7.9.2009/isos/x86_64/
http://mirrors.ustc.edu.cn/centos/7.9.2009/isos/x86_64/
http://mirrors.163.com/centos/7.9.2009/isos/x86_64/
http://mirrors.bfsu.edu.cn/centos/7.9.2009/isos/x86_64/
http://mirrors.nju.edu.cn/centos/7.9.2009/isos/x86_64/
http://mirrors.njupt.edu.cn/centos/7.9.2009/isos/x86_64/
http://mirrors.tuna.tsinghua.edu.cn/centos/7.9.2009/isos/x86_64/
http://ftp.sjtu.edu.cn/centos/7.9.2009/isos/x86_64/
http://mirrors.huaweicloud.com/centos/7.9.2009/isos/x86_64/
http://mirrors.cqu.edu.cn/CentOS/7.9.2009/isos/x86_64/
