Migrate CentOS 7 to AlmaLinux 9: Complete 2026 Guide

With the official end of life of CentOS 7 in June 2024, thousands of production servers were suddenly left without security patches, bug fixes, or vendor support. For companies that have been using CentOS as the foundation of their infrastructure, this was not just an inconvenience but a serious operational and security issue. Using an unsupported operating system increases the risk of vulnerabilities, compliance issues, and unexpected failures.

However, there is a clear way out. AlmaLinux 9 is one of the most suitable alternatives to CentOS, offering full compatibility with RHEL, long-term support, and a solid foundation in the community. It provides the same level of stability and predictability that users of CentOS have been relying on, but with alignment to modern enterprise needs.

This guide is intended for system administrators, DevOps engineers, and infrastructure teams who require a safe and feasible migration plan. Instead of delving into theories, it provides a real-world and production-proven migration solution from CentOS 7 to AlmaLinux 9.

Table of Contents

Why Migrate from CentOS 7 to AlmaLinux 9?

Before getting into the technical steps, it’s important to understand why this migration is necessary. Moving away from CentOS 7 is no longer optional; it’s a matter of security, stability, and long-term viability.

1. CentOS 7 Is Officially Unsupported

As of June 30, 2024, CentOS 7 reached its official end of life. This means it no longer receives security updates, bug fixes, or kernel patches. Any newly discovered vulnerability remains unpatched, leaving your servers exposed to potential exploits.

For production environments, this creates serious risks:

Increased chance of security breaches
Compliance issues for regulated industries
Compatibility problems with newer software
Higher operational risk over time

Continuing to run CentOS 7 may work in the short term, but every passing month increases the chance of failures or security incidents.

2. AlmaLinux 9 Is the Most Natural Successor

AlmaLinux was created specifically to fill the gap left by CentOS. Built and backed by the CloudLinux team, it is binary-compatible with Red Hat Enterprise Linux (RHEL), meaning applications that ran on CentOS are designed to work the same way on AlmaLinux.

Key benefits include:

Full 1:1 compatibility with RHEL
Enterprise-grade stability and performance
A predictable release and update cycle
Long-term support through 2032
Free to use, with optional commercial support

For teams that depended on CentOS for years, AlmaLinux feels familiar while providing a more reliable future.

3. Better Security and Modern System Components

AlmaLinux 9 ships with a newer kernel, updated system libraries, and modern cryptographic standards. This improves overall system security and enables better performance, especially on newer hardware and virtualized environments.

You also gain access to newer versions of:

OpenSSL and system crypto libraries
Systemd and networking components
Container and virtualization tools

These upgrades help protect your infrastructure against modern attack vectors while improving system reliability.

4. Future-Proofing Your Infrastructure

Migrating to AlmaLinux 9 ensures your entire software stack remains supported and compatible. Databases, web servers, control panels, and automation tools increasingly drop support for older operating systems. Staying on CentOS 7 will eventually block upgrades and force emergency migrations later.

By migrating now, you:

Avoid rushed, high-risk upgrades in the future
Maintain compatibility with modern software
Keep vendor and third-party support intact
Create a stable platform for long-term growth

5. A Smarter Move Than Waiting

Many organizations delay migrations because systems appear to be “working fine.” The reality is that unsupported systems degrade quietly until something breaks or worse, gets compromised. Proactively moving to AlmaLinux 9 gives you time to test, plan, and migrate on your own terms.

In short, migrating from CentOS 7 to AlmaLinux 9 isn’t just about replacing an operating system. It’s about securing your environment, maintaining stability, and ensuring your infrastructure is ready for the years ahead.

Preparing for Migration—Don’t Skip This Step

This is where most failed migrations happen in the rush. A few hours of prep now can save you days of troubleshooting later.

1. Take Full Backups

Back up everything — system configuration, databases, and critical app data.
Use:

rsync -aAXv / /mnt/backup/
mysqldump -u root -p --all-databases > /mnt/backup/all_dbs.sql

Or rely on your provider’s snapshot feature (e.g., MainVPS offers instant snapshots on all VPS and dedicated plans).

2. Check Hardware & Software Compatibility

AlmaLinux 9 uses a newer kernel (5.14) and newer libraries. Ensure:

Your control panels (cPanel, Plesk, DirectAdmin) support Alma 9
Your apps don’t depend on older glibc or Python 2.x
You have at least 2 GB of RAM and 20 GB of disk space for the upgrade process

3. Update CentOS 7 Fully

Make sure your CentOS 7 system is fully up to date:

sudo yum update -y
sudo reboot

Step-by-Step: Migrating CentOS 7 → AlmaLinux 9

The official AlmaLinux team provides a migration tool called ELevate. It handles major-version transitions — not just upgrades within CentOS but across the RHEL family (CentOS 7 → AlmaLinux 8 → 9).

Here’s how to use it safely.

Step 1: Install ELevate Tool

Enable EPEL repo first:

sudo yum install -y epel-release

Add the ELevate repository and tool:

sudo yum install -y https://repo.almalinux.org/elevate/elevate-release-latest-7.noarch.rpm
sudo yum install -y leapp leapp-data-almalinux

Step 2: Run a Pre-Upgrade Check

Before you actually upgrade, audit your system for blockers:

sudo leapp preupgrade

This generates /var/log/leapp/leapp-report.txt — a detailed report of issues like:

Unsupported kernels
Removed packages
Custom SELinux policies

Read it carefully. The tool even lists suggested fixes.

Step 3: Resolve Issues

Common quick fixes:

Remove old Python 2 modules or legacy PHP versions.
Disable unsupported repos: sudo yum-config-manager --disable repository-name
Uninstall EOL packages: sudo yum remove package-name

Once everything looks clean, proceed.

Step 4: Run the Upgrade to AlmaLinux 8

sudo leapp upgrade
sudo reboot

The system reboots into an AlmaLinux 8 environment.
Check:

cat /etc/os-release

You should see AlmaLinux 8.x.

Step 5: Upgrade AlmaLinux 8 → AlmaLinux 9

Now that you’re on 8, the jump to 9 is straightforward.

sudo dnf install -y dnf-plugin-system-upgrade
sudo dnf system-upgrade download --releasever=9 -y
sudo dnf system-upgrade reboot

After reboot, verify:

cat /etc/redhat-release

Output should read:

AlmaLinux release 9.x (Emerald Puma)

Congratulations—your system is officially running AlmaLinux 9!

Post-Migration: Tune and Verify

Check System Health

Run:

sudo dnf update -y
sudo dnf autoremove -y
sudo reboot

Re-enable SELinux (if you disabled it)

sudo setenforce 1

Verify Core Services

Check web, database, and mail services:

systemctl status nginx
systemctl status mariadb
systemctl status postfix

If you’re using control panels, ensure they detect Alma 9 correctly.

Hardening AlmaLinux 9 for Production

Now that you’re live on AlmaLinux 9, lock it down.

Firewall & Security

sudo dnf install firewalld -y
sudo systemctl enable firewalld --now
sudo firewall-cmd --permanent --add-service=http
sudo firewall-cmd --permanent --add-service=https
sudo firewall-cmd --reload

Intrusion Protection

Install Fail2Ban and enable automatic banning of brute-force attempts:

sudo dnf install fail2ban -y
sudo systemctl enable fail2ban --now

Automatic Updates

sudo dnf install dnf-automatic -y
sudo systemctl enable --now dnf-automatic.timer

Performance Tweaks Worth Doing

Enable HTTP/2 and Gzip in Nginx or Apache.
Tune MariaDB using mysqltuner.pl.
Enable swap if your VPS has under 2 GB RAM.
Use a local VPS provider like MainVPS India for lower latency and faster package downloads.

Lessons from Real Migrations

I’ve helped several businesses move production workloads from CentOS 7 to Alma 9.
Here’s what experience teaches you:

Read the pre-upgrade report—don’t ignore even minor warnings.
Remove cPanel before migration and reinstall it after; the same for Plesk.
Test in staging first if your server runs critical apps.
Have console access ready. If SSH fails after reboot, you can still fix boot issues via console.
Clean up legacy services (like old PHP-FPM 5.x) that might not exist in Alma 9.

Final Thoughts

Upgrading from CentOS 7 to AlmaLinux 9 is more than just a simple operating system upgrade; it’s a long-term commitment to ensuring the continued stability, security, and supportability of your environment for years to come. With CentOS 7 no longer receiving updates, continuing to run on this version only adds risk and technical debt with the passage of time.

With the help of the ELevate tool and proper planning, you can now approach this upgrade in a controlled and predictable manner. When done properly, you can now ensure that existing configurations are maintained, downtime is avoided, and your production environment is migrated to the new version without any unexpected downtime.

If your servers are still running CentOS 7, this is the perfect time to take action. The first step is to perform complete backups and then test the upgrade process on a staging environment before proceeding.

Frequently Asked Questions (FAQs)

1. Is AlmaLinux 9 a direct drop-in replacement for CentOS 7?

Not exactly. AlmaLinux 9 uses a newer kernel, updated system libraries, and the modern dnf package manager instead of yum. However, application compatibility remains very high, especially for standard web, database, and enterprise workloads. Most applications that ran on CentOS 7 can be adapted with minimal changes.

2. How long will AlmaLinux 9 receive updates and support?

AlmaLinux 9 is supported until 2032, including security patches and critical updates. This provides a long and predictable support lifecycle, making it suitable for production environments that require stability over many years.

3. Can I upgrade directly from CentOS 7 to AlmaLinux 9?

The supported upgrade path is CentOS 7 → AlmaLinux 8 → AlmaLinux 9. While this may sound complex, both upgrades can be performed in a single, well-planned maintenance window using the ELevate tool. Skipping intermediate versions is not recommended.

4. Will my existing applications be compatible with the new environment?

In most instances, yes. However, applications that depend on deprecated components such as Python 2, older PHP versions, or older system libraries may need to be updated or replaced. It is highly recommended that you test your applications in a pre-migration staging environment.

5. Can I retain my existing cPanel or Plesk environment?

In most instances, control panels must be reinstalled on AlmaLinux 9 in order to achieve optimal compatibility. Prior to migration, it is highly recommended that you create a backup of all configurations, data, and licenses.

6. What is the safest rollback option in case the migration fails?

The safest rollback option is to restore from a full server snapshot or system backup. Creating a snapshot of the server before using the Elevate tool enables an immediate rollback in case of any issues. Rollback planning is always a consideration in your migration planning.

7. How much downtime can I expect during the migration process?

The amount of downtime required during migration depends on the size of the server, the packages installed, and the services. With careful planning and testing, many migrations can be accomplished in a matter of hours. Performing maintenance during low-traffic times helps keep the impact on users to a minimum.

8. Do I have to change my hosting company to install AlmaLinux 9?

Not necessarily, but your hosting company has to support AlmaLinux 9 and have hardware and virtualization compatible with AlmaLinux 9. A hosting company that provides fast storage, up-to-date CPUs, and root access will make the transition and management process much easier.

9. Can I use AlmaLinux 9 for production purposes?

Yes. AlmaLinux 9 is an enterprise distribution, providing compatibility with RHEL, long-term support, robust security settings, and predictable updates. AlmaLinux 9 is commonly used for hosting, databases, application servers, and virtualization software.

10. Where should I host a new AlmaLinux 9 server?

Choose a reliable provider with low latency, modern infrastructure, and strong support. For businesses targeting Indian users, a VPS or dedicated server hosted in India can offer better performance and lower latency, along with full root control for advanced configurations.