Seamless Migration: A Step-by-Step Guide to Transitioning from CentOS 8 to Rocky Linux

With CentOS 8 reaching its end of life, systems dependent on it risk security vulnerabilities and lack of support. Transitioning to Rocky Linux ensures continuity, stability, and long-term viability for enterprise and cloud deployments.

Forget quick-fix scripts. Real migration demands a controlled, well-documented process that respects existing configurations and minimizes downtime — we break down how to do it right, not just fast.

Why Migrate from CentOS 8 to Rocky Linux?

CentOS 8 officially ended support in December 2021, meaning no more security updates or bug fixes. For organizations running critical workloads, this is a ticking time bomb for stability and security. Rocky Linux emerged as a community-driven, enterprise-grade replacement that’s binary-compatible with Red Hat Enterprise Linux (RHEL), making it the natural successor many sysadmins trust.

If you want a resilient system that mirrors your current CentOS 8 environment with minimal disruption, Rocky Linux is your go-to choice.

Prerequisites Before Migration

• System Backup: Full system backup is non-negotiable. Use tools like rsync, tar, or take snapshots if on virtualized/cloud platforms.
• Root or Sudo Access: You’ll need elevated privileges for installation tasks.
• Internet Connectivity: Access to Rocky Linux repositories.
• Check Current System: Know your kernel version, installed packages, and services.

cat /etc/os-release       # Confirm it's CentOS 8
uname -r                  # Check kernel version
rpm -qa --qf '%{NAME}\n'  # List installed packages

Step 1: Prepare Your Environment

Make sure your system is fully updated before you start:

sudo dnf clean all
sudo dnf update -y
sudo reboot

After rebooting back into your fully-patched CentOS 8 environment, confirm again your version:

cat /etc/centos-release

Step 2: Disable Third-Party Repositories and EPEL

Third-party repos can cause conflicts during migration.

sudo dnf repoquery --repoid='*' | grep -v '^epel'

Disable all non-base repos besides EPEL (because you’ll reinstall it later):

sudo dnf config-manager --disable <repo-id>

It’s good practice to document these repos so you can re-enable them post-migration.

Step 3: Install the Rocky Linux Migration Script

Rocky Linux provides an official migration tool called migrate2rocky which assists with converting CentOS systems seamlessly.

First, fetch and run the script:

curl -O https://raw.githubusercontent.com/rocky-linux/rocky-tools/main/migrate2rocky/migrate2rocky.sh
chmod +x migrate2rocky.sh
sudo ./migrate2rocky.sh -r

What does this do?

• Converts repo files from CentOS to Rocky.
• Migrates RPM packages by replacing CentOS-specific ones with Rocky ones.
• Does basic dependency cleaning and system refresh.

Note: This script supports migrations from CentOS 8 to Rocky Linux 8 directly.

Step 4: Validate Before Accepting Changes

Before making irreversible changes, run the script in “check” mode:

sudo ./migrate2rocky.sh -c

This will perform a dry run highlighting:

• Potential package conflicts.
• Configuration files that may be overwritten.
• Packages being replaced or removed.

Review these carefully. If anything critical is listed (e.g., custom kernel modules, proprietary drivers), plan accordingly before continuing.

Step 5: Execute Migration

If the dry run looks good, proceed without the check flag:

sudo ./migrate2rocky.sh -r

During this process:

• Your OS release files under /etc will swap out to Rocky Linux equivalents.
• RPMs will be updated.
• Basic system metadata will update Rocket-specific signatures.

Be patient—the process can take some time depending on package count and network speed.

Step 6: Clean Up & Post-Migration Tasks

After migration completes:

1. Reboot into new Rocky Linux system:

   sudo reboot
   

2. Confirm release identity:

   cat /etc/os-release
   

   Example output should show something like:

   NAME="Rocky Linux"
   VERSION="8.x"
   ID="rocky"
   

3. Re-enable your third-party repositories one by one; test functionality after each before applying updates.

4. Reinstall EPEL if necessary:

   sudo dnf install epel-release -y 
   

5. Update all packages for consistency:

   sudo dnf update -y && sudo dnf clean all 
   

6. Verify services are running as expected:

   sudo systemctl status <service-name>
   

7. Check logs for any warnings/errors (journalctl -xe).

Step 7: Test Everything Thoroughly

Migration isn’t complete until you verify key workloads:

• Web services (Apache/Nginx)
• Database instances (MariaDB/PostgreSQL)
• Application runtimes (Java/Python/Node)

Check application logs carefully and consider deploying test workloads before shifting production traffic back on.

Optional: Automate With Ansible or Scripts

If you manage multiple hosts, consider automating the migration steps with configuration management tools like Ansible (example snippet):

- name: Migrate CentOS 8 to Rocky Linux using migrate2rocky script 
  hosts: centos_servers  
  become: yes  
  tasks:
    - name: Download migrate2rocky.sh  
      get_url:
        url: https://raw.githubusercontent.com/rocky-linux/rocky-tools/main/migrate2rocky/migrate2rocky.sh  
        dest: /tmp/migrate2rocky.sh  
        mode: '0755'

    - name: Run migrate2rocky script  
      command: /tmp/migrate2rocky.sh -r  
      register: migration_output  

    - debug:
        var: migration_output.stdout_lines  

Automating ensures consistency across systems — crucial when orchestrating at scale.

Troubleshooting Tips

For detailed debug logs, review /var/log/migrate2rocky.log.

Final Words

Migrating from CentOS 8 to Rocky Linux doesn’t have to be risky or rushed. By following a structured approach — backing up data, verifying repos and dependencies, using official tools, and thoroughly testing — you ensure high availability and future-proof stability without surprises.

Remember: good migrations are about precision over speed — avoid quick-fix scripts promising magic solutions. With Rocky Linux’s strong community support and compatibility guarantees, your servers will be ready for years of secure operation ahead.

Happy migrating!

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