Create a repository to update an offline Red Hat Enterprise Linux system

When running a RHEL server without internet connection, it cannot receive upgrades.
But with a RHEL system with the same major release that is online, it is possible to download the required packages and dependencies.

To limit the version to any specific version (8.8 in this example), use: 

subscription-manager release --set 8.8

To get the latest version 

subscription-manager release --unset

Clear the cache: 

rm -rf /var/cache/dnf

Create the directory for the repo: 

mkdir /opt/rhel
mkdir /opt/rhel/8

Download the packages for the OS and applications: 

reposync -p /opt/rhel/8 --download-metadata --repoid=rhel-8-for-x86_64-baseos-rpms 
reposync -p /opt/rhel/8 --download-metadata --repoid=rhel-8-for-x86_64-appstream-rpms

Update the offline Red Hat Enterprise Linux system

Coning soon …