Migrating CentOS 8 to CentOS 8 Stream is surprisingly as easy as maybe updating to the next version of CentOS itself!

First things first… Update the current system to the latest version of all the software packages. This ensures that firstly your yum repository cache itself is up to date and also updates the packages to the latest
sudo yum -y update

Now lets install dnf – DNF is the software package manager that installs, updates, and removes packages and is a successor to yum
sudo yum -y install dnf

Just to know that we are indeed on CentOS 8 before begining the migration, check the current version of CentOS
sudo cat /etc/centosos-release

Disable current CentOS 8 linux repository and replace them with their corresponding CentOS 8 Stream ones
sudo dnf --disablerepo '*' --enablerepo extras swap centos-linux-repos centos-stream-repos

sudo sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-*

sudo sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-*

Its time to synchronize the latest distributions of all the software packages meant for CentOS 8 Stream
sudo dnf distro-sync

Finally, reboot the system
sudo reboot

Moment of truth. Once the server is back online after the reboot, check the OS version post the upgrade
sudo cat /etc/centos-release

That’s it!