Centos8.4.2105升级源

[root@ns518 wp-content]# yum update
CentOS Linux 8 - AppStream                                             197  B/s |  38  B     00:00    
Error: Failed to download metadata for repo 'appstream': Cannot prepare internal mirrorlist: No URLs in mirrorlist

https://serverfault.com/questions/1093922/failing-to-run-yum-update-in-centos-8

sed -i 's|baseurl=http://vault.centos.org|baseurl=http://vault.epel.cloud|g' /etc/yum.repos.d/CentOS-Linux-*