Building a DNF/YUM mirror from ULN
It is very common for admins to not enable internet access for the systems running in a secure network, like banking of Government networks. A local mirror of Oracle’s Unbreakable Linux Network (ULN) is a great way to allow systems to access patches without having to reach out across the internet to access them.
Getting ready
To do this, you will need a YUM server system running Oracle Linux 8. The local system should have internet access to be able to reach the ULN servers via direct access or a proxy server. Only the system (often called a YUM server) synchronizing to ULN will require this access; all the systems using this system will not need access to the internet, they will use this system to access patches.
The system is not CPU- or RAM-intensive – 2 cores and 4 GB of RAM are often more than enough for the server, but the system will use a lot of disk space. You can check how much space is needed by running the dnf repolist...