How to Fix Error: Failed to Download Metadata for Repo ‘AppStream’ Centos 8

What is the Cause of This Error?

You may well be aware that CentOS Linux 8 died a premature death, it reached the End Of Life (EOL) on December 31st, 2021, thus it no longer receives development resources from the official CentOS project.

This means that after Dec 31st, 2021, to update your CentOS installation, you are required to change the mirrors to CentOS Vault Mirror, where they will be archived permanently.

How to Fixed it?

[root@~]# cd /etc/yum.repos.d/
[root@~]# sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-*
[root@~]# sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-*