Seamless Migration: Step-by-Step Guide to Transition from CentOS 8 to AlmaLinux

With CentOS 8 reaching its end-of-life (December 31, 2021), countless organizations are at a crossroads. Maintaining server stability and security is no longer viable on an unsupported platform, and migrating to a reliable alternative is imperative. AlmaLinux has quickly emerged as a community-driven, enterprise-grade replacement compatible with Red Hat Enterprise Linux (RHEL) — making it the ideal choice for those seeking continuity without disruption.

Skip the fear and myths around migrating from CentOS 8; this guide delivers a precise, battle-tested roadmap that system admins can trust to execute a smooth shift to AlmaLinux with zero downtime and minimal risk.

Why Migrate from CentOS 8 to AlmaLinux?

CentOS has long been the go-to for RHEL-compatible servers without the subscription cost — but CentOS 8’s sudden EOL announcement caught many by surprise. Running servers on unsupported OS versions exposes you to:

• Security vulnerabilities
• Lack of software updates
• Compatibility issues with newer applications

AlmaLinux steps in as a binary-compatible fork of RHEL maintained by the community, promising:

• Stability backed by enterprise-grade reliability
• Regular security patches and updates
• Compatibility with existing CentOS-based infrastructure and tools

Prerequisites Before Migration

Before diving in, make sure:

• You backup your data (use rsync, tar, or snapshots)
• You have root or sudo access
• Your current system is fully updated (sudo dnf update -y)
• You have access to the server console in case of emergencies

Step-by-Step Migration Process

Here’s how you can switch your CentOS 8 server over to AlmaLinux with minimal fuss.

1. Update Existing CentOS 8 System

Ensure your system is fully up-to-date so there are no package conflicts:

sudo dnf clean all
sudo dnf update -y
sudo reboot

2. Install ELevate Tool (Official Migration Utility)

The AlmaLinux team provides ELevate, an official tool designed for OS-level conversion across major distributions.

sudo dnf install -y https://repo.almalinux.org/elevate/elevate-release-latest.el8.noarch.rpm
sudo dnf install -y leapp-upgrade leapp-data-almalinux

3. Pre-Migration Checks

Run pre-upgrade checks that scan your system for potential blockers:

sudo leapp preupgrade

Inspect output at /var/log/leapp/leapp-preupgrade.log for any issues.

4. Begin Migration Process

Assuming pre-upgrade check passes without critical errors:

sudo leapp upgrade --target almalinux8

This command prepares files and settings to convert the OS.

5. Reboot into ALMA Linux Environment

Once leapp finishes, reboot your server:

sudo reboot

On boot, your system should now be running AlmaLinux.

6. Verify AlmaLinux Installation

Confirm that migration was successful:

cat /etc/os-release

Output should include:

NAME="AlmaLinux"
VERSION="8.x"
ID="almalinux"

Also validate release version:

rpm -q almalinux-release

Optional: Configure Repositories & Clean Up

Replace any CentOS-specific repos with AlmaLinux equivalents if necessary:

sudo dnf remove centos-linux-repos centos-gpg-keys -y
sudo dnf install almalinux-release -y
sudo dnf distro-sync -y 

Clean caches and old packages:

sudo dnf clean all && sudo dnf autoremove -y 

Real-Life Example: Migrating a Web Server

If you run services like Apache or NGINX, verify everything post-migration like so:

sudo systemctl status httpd.service   # For Apache servers OR:
sudo systemctl status nginx.service   # For NGINX servers

Then test app functionality or website availability as usual.

Troubleshooting Tips

For extensive issues consult the official AlmaLinux migration documentation.

Final Thoughts

Migrating from CentOS 8 to AlmaLinux doesn’t have to be complex or risky. With proper preparation and the right tooling like ELevate, you can preserve your workloads’ stability and security effortlessly — safeguarding your infrastructure for years ahead.

Don’t let CentOS EOL cause downtime or headaches. Begin your seamless transition today!

If you found this guide helpful, feel free to share it or leave questions below — happy migrating!