https://serverfault.com/questions/904304/could-not-resolve-host-mirrorlist-centos-org-centos-7/904307#
/etc/resolv.conf
nameserver 9.9.9.9
Save this file, then try yum update again.
标签：serverfault,file,centos,配置,yum,9.9,conf
来源： https://www.cnblogs.com/leowindy/p/15315991.html