404 on cpanel-plugins repository related to os_name_prefix

Symptoms

When attempting to update via yum/dnf or upcp, you may experience an error similar to the following:

CONFIG_TEXT: Errors during downloading metadata for repository 'cpanel-plugins': - Status code: 404 for http://httpupdate.cpanel.net/cpanel-plugins-$os_name_prefix8-x86_64-mirrorlist (IP: ) - Status code: 404 for http://httpupdate.cpanel.net/cpanel-plugins-$os_name_prefix8-x86_64-mirrorlist (IP: ) 
Error: Failed to download metadata for repo 'cpanel-plugins': Cannot prepare internal mirrorlist: Status code: 404 for http://httpupdate.cpanel.net/cpanel-plugins-$os_name_prefix8-x86_64-mirrorlist (IP: )

Cause

This can occur when the /etc/yum/vars/os_name_prefix is missing.

Resolution

1. Log in to the server via SSH or WHM's Terminal as the root user

2. Run the following command to generate the data for your server:

   # /usr/local/cpanel/3rdparty/bin/perl -MCpanel::Yum::Vars -e 'Cpanel::Yum::Vars::install()'