Rocky Linux vs AlmaLinux: Which CentOS Replacement is Right for You?

When Red Hat ended CentOS in December 2020, it left a gap that a lot of production infrastructure depended on. Two distributions moved to fill it: Rocky Linux and AlmaLinux. Both are free, both are RHEL-compatible, and both are still around and actively maintained years later.

This post walks through where each project came from, how their compatibility models diverged after Red Hat restricted source access, and what that means if you're choosing one for a VPS.

TL;DR

Neither Rocky Linux nor AlmaLinux wins outright. Both are mature, actively maintained CentOS replacements still in wide production use, and the difference comes down to approach.

• Rocky Linux pursues strict bug-for-bug compatibility with RHEL and is governed by a dedicated nonprofit (the RESF) with no single corporate controller
• AlmaLinux offers ABI compatibility rather than a byte-for-byte rebuild, and is backed primarily by CloudLinux alongside its own foundation
• Want the closest thing to a literal RHEL clone, plus governance with no dominant sponsor? Go Rocky
• Want ABI compatibility that's good enough for your workload, a strong anchor sponsor, and support for older x86-64-v2 hardware? AlmaLinux is an equally solid pick
• For most standard VPS workloads, the practical difference is small

The history behind two RHEL rebuilds

Rocky Linux was started by Gregory Kurtzer, one of the original creators of CentOS, and named in tribute to his late CentOS co-founder, Rocky McGaugh. It's governed by the nonprofit Rocky Enterprise Software Foundation (RESF). AlmaLinux was announced by CloudLinux, a hosting-focused RHEL derivative vendor, and is governed by its own nonprofit foundation.

Both projects rebuilt RHEL from its public source RPMs, package for package, until mid-2023, when Red Hat restricted public source access. That forced a split: Rocky kept pursuing bug-for-bug compatibility, sourcing packages through CentOS Stream, RHEL's Universal Base Images, and cloud provider access to RHEL. AlmaLinux shifted its goal to ABI (application binary interface) compatibility, building primarily from CentOS Stream so that software built for RHEL runs correctly on AlmaLinux even when the packages aren't byte-identical.

Comparing Rocky Linux and AlmaLinux

Both distributions solve the same problem, but the practical differences show up in a handful of specific areas: who backs each project, what hardware they support, how their ecosystems have started to diverge, and where each stands on compliance. Here's how they actually compare.

Governance

Rocky has no single corporate backer. AlmaLinux does.

Rocky Linux is run by the RESF, with commercial support available through CIQ. Kurtzer's original framing was explicitly a reaction against a single company being able to unilaterally end a project, the way Red Hat ended CentOS. AlmaLinux is governed by its own nonprofit foundation, but CloudLinux remains its primary financial backer, reportedly contributing around a million dollars a year alongside engineering resources, with the foundation's sponsor base having broadened over time to include names like AWS and ARM on its board.

Hardware support

AlmaLinux still builds for older CPUs that Rocky and RHEL itself have left behind.

With RHEL 10, Red Hat raised its minimum CPU baseline to x86-64-v3, roughly Intel Haswell-era processors from 2015 onward. Rocky Linux 10 follows that same baseline. AlmaLinux additionally offers a separate x86-64-v2 build for organizations still running older hardware that doesn't meet the v3 requirement, which can matter for older physical servers but is unlikely to affect anyone deploying on a current-generation VPS.

Support lifecycle

Both distributions follow RHEL's own 10-year lifecycle shape: an Active Support phase followed by a longer Security Support phase. Rocky Linux 8 runs through May 2029, Rocky 9 through May 2032, and Rocky 10 through May 2035. AlmaLinux mirrors that same schedule for its equivalent major versions. Within either project, though, only the current minor release stays patched: once a new minor ships, the previous one stops receiving updates immediately, unlike RHEL's own Extended Update Support windows. If you need to stay pinned to a specific minor for longer, commercial extended support is available through TuxCare for AlmaLinux or CIQ for Rocky.

Ecosystem

Core tooling is identical between the two. Third-party vendor support is where they now genuinely diverge, and this is the one place a decision has already been made for you if you use certain hosting software.

cPanel & WHM announced it will discontinue support for Rocky Linux 8 and 9 starting with version 134, citing AlmaLinux's higher adoption in the RHEL-compatible ecosystem. If you're running or planning to run cPanel, existing Rocky Linux servers will need to migrate to AlmaLinux before that upgrade, and new cPanel installs on Rocky are blocked going forward. Outside of cPanel specifically, DNF, SELinux, systemd, and general tooling remain consistent across both distributions.

Performance

Neither distribution has a performance edge over the other (this has been tested directly).

Phoronix ran a series of server benchmarks comparing Rocky Linux 10, AlmaLinux 10, and RHEL 10 on identical hardware and found performance essentially on par across the board, which makes sense, since all three share the same kernel and package sources.

Security

Both ship secure by default, but their compliance certifications are at different stages right now.

AlmaLinux 9.2 holds its own FIPS 140-3 validated cryptographic modules on NIST's active list, funded through CloudLinux's TuxCare division, making it the first EL9 distribution with a validated kernel module. Rocky Linux's modules, backed by CIQ, are on NIST's "Modules in Process" list working toward that same validation but aren't yet listed as fully active. If FIPS 140-3 validation is a requirement for you, check the current status directly, since both are actively moving through the pipeline.

How to migrate your OS

Both projects have a supported, in-place migration path, so you don't need a fresh install to switch, though the path depends on where you're starting from.

If you're on an existing EL8 or EL9 system (CentOS or another RHEL rebuild), Rocky provides migrate2rocky and AlmaLinux provides almalinux-deploy, both of which convert the system in place by swapping release packages and resyncing against the target distribution's repos. If you're still on CentOS 7, there's no direct jump to a current release: the conversion has to go through one major version at a time using Leapp-based tooling (7 to 8, then 8 to 9), and each hop runs its own pre-flight check that can surface blocking issues, like loaded kernel modules that no longer exist in the target release. Whichever path you take, there's no built-in rollback once a conversion starts, so a full snapshot or image-level backup beforehand is a must.

Common migration issues

The migration tools themselves are reliable. Most real-world failures come from things layered on top of the base system:

• A stale third-party kernel module conflicting with the package swap
• A UEFI system landing at a bare GRUB prompt after conversion (Secure Boot needs to be disabled beforehand)
• Control panel software like cPanel or Plesk hitting dependency conflicts during the resync
• Leftover packages from a Stream-only or vendor repo causing conflicts after the fact

None of these are common enough to expect on every run, but common enough that testing the conversion on a snapshot or throwaway clone first, rather than a production box, is worth the extra hour.

Which one fits your use case?

If you want a quick gut check based on what you're optimizing for:

The bottom line

Both distributions are mature, both have survived a major disruption to their supply chain in 2023 without folding, and both are widely deployed in production today. If you want the closest thing to a literal RHEL rebuild and prefer a governance model with no single corporate controller, Rocky Linux is the more direct match for what CentOS used to be. If ABI compatibility is sufficient for your needs and you're comfortable with a foundation that has a strong anchor sponsor, AlmaLinux is an equally solid, well-supported choice, and its x86-64-v2 builds are a genuine advantage if you're stuck on older hardware.

For most standard web and application workloads, the practical difference between running one or the other is small. The bigger factor is usually which one your team already has operational familiarity with, or which one your specific third-party software vendor officially supports.

VPSServer.com offers both AlmaLinux and Rocky Linux as supported operating systems, along with a wide range of others, including Ubuntu, Debian, Fedora, Linux Mint, as well as Windows Server and Desktop versions. If you're migrating an existing CentOS or RHEL workload, either distribution should get you there with minimal friction.

The author

Rachel Burstyn

Rachel Burstyn is a tech writer and content strategist specializing in B2B software and cloud infrastructure. She creates technical and marketing content across formats, making complex topics accessible to the people who need to understand them.