Rocky Linux: Versions, RHEL Compatibility & Migration

This is a working reference on Rocky Linux — the same material our Linux server support team uses when assessing RHEL-family estates. It covers what Rocky Linux is, current versions and their support dates, how the project maintains compatibility with Red Hat Enterprise Linux, migrating from CentOS, and how Rocky compares with AlmaLinux.

What is Rocky Linux

Rocky Linux is a free, community-built enterprise Linux distribution designed to be 1:1 binary compatible with Red Hat Enterprise Linux (RHEL). It was founded in December 2020 by Gregory Kurtzer, a co-founder of the original CentOS project, immediately after Red Hat announced it was discontinuing classic CentOS Linux in favor of CentOS Stream. Classic CentOS had been a free downstream rebuild of RHEL; Stream sits upstream of RHEL, which removed the stable, RHEL-identical option many production environments depended on. Rocky Linux was created to fill that gap — the project's own history is documented at rockylinux.org/about.

The project is hosted by the Rocky Enterprise Software Foundation (RESF), a public benefit corporation set up to keep the distribution community-controlled rather than owned by a single vendor. The name honors Rocky McGaugh, a co-founder of the original CentOS project who died before its success.

Versions and support dates

Rocky Linux tracks RHEL major releases and inherits their ten-year lifecycle: roughly five years of active support with minor releases every six months, then five years of security and bug-fix maintenance. Dates are published on the Rocky Linux version wiki.

Rocky 8 is frozen at 8.10 and receives security fixes only. Rocky 9 and 10 continue to receive minor releases (9.7 and 10.1 as of late 2025), each landing shortly after the corresponding RHEL minor release. These dates match the RHEL 8, 9, and 10 lifecycles — background on the upstream product is in our Red Hat Enterprise Linux overview.

RHEL compatibility: the bug-for-bug model

Rocky Linux rebuilds RHEL from source with the goal of bug-for-bug compatibility: the same package versions, the same ABI, and — where a bug exists in RHEL — the same bug in Rocky. Software certified or tested against a given RHEL release is expected to behave identically on the matching Rocky release. Branding, trademarks, and subscription tooling are the intended differences.

In June 2023, Red Hat stopped publishing RHEL source packages to git.centos.org and limited srpm access to its customer portal, whose subscription terms restrict redistribution. Rocky Linux responded by changing where it obtains sources, not what it builds. As described in the project's statement Keeping Open Source Open, Rocky now obtains RHEL sources through UBI container images (published to public registries such as Docker Hub) and through pay-per-use public cloud instances of RHEL, where sources are fetched via dnf in automated CI pipelines. The project's position is that the GPL guarantees the right to redistribute those sources once lawfully obtained.

Migrating from CentOS

The supported migration tool is migrate2rocky, maintained in the official rocky-tools repository on GitHub. It converts a running CentOS, CentOS Stream, AlmaLinux, RHEL, or Oracle Linux system in place by swapping repositories and reinstalling packages from Rocky mirrors. The procedure, per the official migration guide: download the script (migrate2rocky.sh for version 8 systems, migrate2rocky9.sh for version 9), make it executable, and run ./migrate2rocky.sh -r. The -r flag performs the full conversion.

Standard precautions apply regardless of path: full backups or snapshots first, third-party repositories (EPEL survives; vendor repos may not) reviewed, and the migration tested on a clone before touching production.

Rocky Linux vs AlmaLinux

AlmaLinux launched in the same window, for the same reason, and the two are the main CentOS replacement options. The practical differences:

After the 2023 source changes, the projects diverged in philosophy: Rocky held to exact RHEL reproduction, while AlmaLinux dropped the bug-for-bug goal in favor of ABI compatibility, which lets it patch faster or fix bugs Red Hat has not. Either is a valid CentOS replacement; the choice usually comes down to whether exact RHEL parity matters for vendor certification. A fuller profile of the alternative is in our AlmaLinux reference.

Commercial support

Rocky Linux itself carries no vendor support contract. CIQ, the company founded by Gregory Kurtzer and a founding sponsor of the project, sells commercial support, hardened builds, and long-term support offerings for Rocky Linux.

Packages and updates

Rocky uses the same tooling as RHEL: dnf for package management, RPM packages, dnf modules/AppStream on 8 and 9, systemd, SELinux enabled by default, and firewalld. Routine patching is dnf update against the Rocky mirrors; errata are published so security updates can be filtered and audited. EPEL provides the extra-packages layer, exactly as it did on CentOS. Administration guides are maintained at docs.rockylinux.org.

Who runs Rocky Linux

Rocky's largest constituencies are the ones classic CentOS served: high-performance computing (Kurtzer's background — HPC clusters standardize on RHEL-compatible images), web hosting providers, and enterprises running RHEL-certified software without RHEL subscriptions on every node. cPanel supports Rocky Linux as an installation OS, which keeps it common on hosting servers, and the major clouds (AWS, Azure, Google Cloud) publish official Rocky images.

FAQ

Is Rocky Linux free?

Yes. Rocky Linux is free to download, use, and redistribute, with no subscriptions or per-node licensing. Paid support is optional, through CIQ or independent providers.

Is Rocky Linux the same as CentOS?

Functionally it fills the same role classic CentOS did: a free rebuild of RHEL. It is a separate project with separate infrastructure and governance, but was founded by a CentOS co-founder specifically to replace discontinued CentOS Linux.

Which is better, Rocky Linux or AlmaLinux?

Neither is categorically better. Rocky targets exact bug-for-bug RHEL reproduction; AlmaLinux targets ABI compatibility and can diverge on individual fixes. For strict vendor-certification parity, Rocky's model is the closer match; for faster independent patching, AlmaLinux's model allows it.

How long is Rocky Linux supported?

Ten years per major release, matching RHEL. Rocky 8 reaches end of life May 31, 2029; Rocky 9 on May 31, 2032; Rocky 10 on May 31, 2035.