Since this is the fifth time this month that I’ve spun up some CentOS image and been stymied by the inability to install new packages … I’m going to write down the sed commands that magic the default yum repository configuration to something that’s still functional.
cd /etc/yum.repos.d/
sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-*
sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-*