How to migrate from CentOS 8 to Rocky Linux (conversion)

What is Rocky Linux?

Rocky Linux is an open-source operating system and one of the strongest replacement candidates for CentOS 8. It is a 100% binary-compatible release using the Red Hat Enterprise Linux (RHEL). Let us see how to migrate CentOS 8 Linux live server to Rocky Linux 8 using a shell script provided by the Rocky Linux project.

Step 1 – Backup CentOS 8

I started the migration process with backup. I do have nightly backups, but before upgrading, I made a snapshot to revert back when something goes wrong. In other words, keep verified backups.

Step 2 – Installing all updates on CentOS 8

Then I log in using the ssh command:
ssh user@cyburdial-php8-app1

Now, all we have to do is use the dnf command to apply all pending updates:
sudo dnf update

Finally, reboot the Linux box using the shutdown command or reboot command:
sudo reboot

Let us verify CentOS Linux 8 version using the cat command or more command/less command:
more /etc/centos-release

Step 3 – Installing git client on CentOS 8

We need git to install the migration script. Is git installed on the server? Let us find out. Execute the type command:
type -a git

Let us search for the git package, Execute:
dnf list git
dnf search git
dnf info git

Now, install git on your server with the help of the dnf utility, Execute:
sudo dnf install git
type -a git

Clone the repo to install migration tool called rocky-tool

Finally, we need to clone the rocky-tools repo with the help of the git command:
cd /tmp/
git clone https://github.com/rocky-linux/rocky-tools.git
Getting ready for Rocky Linux migration

Step 4 – Migrating from CentOS 8 to Rocky Linux

1. Change the directory using cd command where rocky-tools cloned:
   cd /tmp/rocky-tools/migrate2rocky
2. Set up executable permissions using the chmod command:
   chmod -v +x migrate2rocky.sh
3. Start the migration from CentOS 8 to Rocky Linux by typing the migrate2rocky.sh command:
   ./migrate2rocky.sh -r
   
4. Follow on-screen instructions and wait for some time to finish the migration job. At the end you should see:Done, please reboot your system.
   A log of this installation can be found at /var/log/migrate2rocky.log