AlmaLinux

AlmaLinux is one of the fastest-responding RHEL-compatible distributions to emerge after the end of traditional CentOS. Initiated by CloudLinux, it is now managed by the independent AlmaLinux OS Foundation and is one of the most popular free EL distributions today.

Origin Story

The CentOS EOL Chain Reaction

In December 2020, Red Hat announced that CentOS Linux 8 would reach end-of-life by the end of 2021. This decision impacted millions of users and organizations that relied on CentOS as a free RHEL alternative.

CloudLinux’s Rapid Response

CloudLinux Inc. is a company specializing in shared hosting-optimized Linux, with over 10 years of experience developing RHEL-compatible distributions. Within days of the CentOS EOL announcement, CloudLinux CEO Igor Seletskiy announced a commitment of $1 million per year to create a CentOS replacement.

The project was initially codenamed “Project Lenix” and later officially named AlmaLinux (“Alma” means “soul” in Latin).

Rapid Release

March 2021: AlmaLinux 8.3 officially released, becoming one of the first available CentOS alternatives
Only about 3 months from project announcement to general availability

AlmaLinux OS Foundation

To ensure the project’s long-term independence, CloudLinux transferred management of AlmaLinux to the independent AlmaLinux OS Foundation (a 501(c)(6) nonprofit registered in Delaware, USA) in 2021.

Governance Structure

Board of Directors: Composed of community-elected and sponsor representatives
Membership: Any individual or organization can apply for foundation membership
Transparent operations: Board meeting minutes are public, finances are transparent

Major Sponsors

CloudLinux (founding sponsor)
cPanel
AWS
Microsoft Azure
Numerous hosting service providers

RHEL Compatibility Strategy

AlmaLinux’s RHEL compatibility strategy has undergone one significant shift.

Early Phase: 1:1 Binary Compatible (2021-2023)

Initially, AlmaLinux aimed for 1:1 binary compatibility with RHEL — rebuilding as many packages as possible from the corresponding SRPMs to narrow the gap with RHEL. Note that even in this phase, “every package identical” was a goal rather than a per-package certified guarantee; actual differences follow the official release notes.

Post-2023: ABI Compatible

In June 2023, Red Hat restricted direct access to RHEL source code. On 2023-07-13, AlmaLinux announced an adjustment of its compatibility goal: from a “1:1 rebuild” to ABI / binary compatibility as the target (official announcement). The official wording is “adjusting the goal”, not “giving up compatibility”:

Goal: Application Binary Interface (ABI) compatibility
Programs compiled on RHEL should run on AlmaLinux
May include additional bug fixes or security patches without per-package parity; the reverse direction (binary built on AlmaLinux running on RHEL) is not covered
Sources obtained from CentOS Stream and other publicly available sources

This strategy shift actually gives AlmaLinux greater flexibility, allowing faster delivery of security fixes.

Versions and Releases

AlmaLinux Version	Based on RHEL	Release Date	Support Until	Kernel
AlmaLinux 8	RHEL 8.x	2021-03	2029-05	4.18
AlmaLinux 9	RHEL 9.x	2022-05	2032-05	5.14
AlmaLinux 10	RHEL 10.x	2025-05	2035-05	6.12

These match src/data/distro-profiles.json; status badges are evaluated at build time and lifecycle dates defer to upstream announcements.

AlmaLinux typically releases corresponding versions within days of a RHEL minor release.

Key Tools

almalinux-deploy: In-Place Migration Tool

almalinux-deploy allows migrating existing systems to AlmaLinux in place, without reinstalling:

# Migrate from CentOS Linux 8 to AlmaLinux 8
curl -O https://raw.githubusercontent.com/AlmaLinux/almalinux-deploy/master/almalinux-deploy.sh
sudo bash almalinux-deploy.sh

Supported migration sources:

CentOS Linux 8
RHEL 8 (requires unregistering)
Rocky Linux 8
Oracle Linux 8
CentOS Linux 7 (to AlmaLinux 8 requires ELevate)

ELevate: Cross-Major-Version Upgrade Tool

ELevate is an important project developed by the AlmaLinux community that enables in-place upgrades between different EL major versions:

# Example: Upgrade from EL 7 to EL 8
sudo yum install -y https://repo.almalinux.org/elevate/elevate-release-latest-el7.noarch.rpm
sudo yum install -y leapp-upgrade leapp-data-almalinux

# Pre-upgrade check
sudo leapp preupgrade

# Perform the upgrade
sudo leapp upgrade
sudo reboot

ELevate performs one-step upgrades, with both the source and the target constrained (see the ELevate Quickstart):

Source	Target	Notes
CentOS 7	AlmaLinux 8	Point CentOS 7 repos at the vault or AlmaLinux’s el7 mirror first
AlmaLinux 8 / CentOS Stream 8	AlmaLinux 9, CentOS Stream 9	Only these two EL8 sources are supported
AlmaLinux 9 / CentOS Stream 9	AlmaLinux 10, AlmaLinux Kitten 10, CentOS Stream 10	On x86_64-v2, upgrades to AlmaLinux 10 / Kitten 10 are ELevate NG only (testing)

Three boundaries worth spelling out:

Rocky Linux is not a target: the upstream data packages are leapp-data-almalinux, leapp-data-almalinux-kitten and leapp-data-centos; there is no leapp-data-rocky, and Rocky has no official in-place major-version upgrade.
Two majors cannot be crossed in one step: CentOS 7 to AlmaLinux 10 must be split into two upgrades (upstream has a dedicated guide).
Third-party repository support is limited: EPEL is supported only when upgrading to AlmaLinux; Docker CE, MariaDB, nginx, PostgreSQL and others each have their own support scope, so verify them before upgrading.

Installation and Configuration

Getting AlmaLinux

Download: almalinux.org/get-almalinux

Available image types:

DVD ISO: Full installation image
Minimal ISO: Minimal installation
Boot ISO: Network installation boot
Cloud / Container: Cloud images and container images
Live Media: GNOME and KDE desktop experience

Repository Structure

# View enabled repositories
dnf repolist

# Typical output:
# baseos          AlmaLinux 9 - BaseOS
# appstream       AlmaLinux 9 - AppStream
# extras          AlmaLinux 9 - Extras

Repository	Description
baseos	Core OS packages
appstream	Applications and runtimes
extras	AlmaLinux additional tools (e.g., epel-release)
crb	CodeReady Builder equivalent
highavailability	High availability cluster components
plus	AlmaLinux-specific enhanced packages

Enabling Additional Repositories

# Enable CRB repository (usually needed before installing EPEL)
dnf config-manager --set-enabled crb

# Install EPEL
dnf install -y epel-release

# Install ELRepo (kernels and hardware drivers)
dnf install -y elrepo-release

Commercial Support

While AlmaLinux itself is free, several companies offer commercial support:

TuxCare (a CloudLinux company): Provides enterprise-grade support and extended lifecycle support for AlmaLinux
Various MSPs and system integrators: Offer AlmaLinux-based solutions

Community and Contributing

How to Participate

Forums: forums.almalinux.org
Chat: Mattermost and IRC
Code: github.com/AlmaLinux
Bug Tracking: bugs.almalinux.org

Architecture Support

x86_64
aarch64 (ARM64)
ppc64le (IBM POWER)
s390x (IBM Z)

Comparison with Other EL Distributions

Feature	AlmaLinux	Rocky Linux	CentOS Stream
RHEL compat	ABI compatible	Bug-for-bug	Upstream
Initiator	CloudLinux	Gregory Kurtzer	Red Hat
Governance	Nonprofit foundation	RESF	Red Hat
Unique tools	ELevate	Koji (since 10; Peridot before)	SIGs
Commercial support	TuxCare	CIQ	Red Hat

Summary

AlmaLinux has earned an important position among CentOS alternatives through its rapid response, independent governance, and tools like ELevate. It targets ABI compatibility, trading per-package parity for faster security fixes and more build flexibility — “goal” is not “per-package certification”; actual differences follow the official release notes. Whether migrating from CentOS or building a new EL environment, AlmaLinux is a choice worth serious consideration.