Comparing Rocky Linux vs. RHEL

The Enterprise Linux landscape has experienced no shortage of shakeups in the last couple of years. Now after CentOS 7 EOL, many teams are looking into CentOS alternatives and weighing the value of commercial Linux distros like RHEL, which comes with technical support included, to community-backed free alternatives like Rocky Linux. 

Since they are functionally very similar, Rocky Linux vs. RHEL really comes down to differences in cost and support. In this blog, our expert compares the two distributions with consideration for not just upfront costs, but ongoing maintenance, and discusses why it's wise to pair Rocky Linux with third-party support to reduce your risk.

Rocky Linux vs. Red Hat Enterprise Linux (RHEL)

The main difference between Rocky Linux vs. RHEL is that Rocky Linux is a community-developed, free alternative to RHEL, which is a commercial solution requiring a paid subscription.

Any discussion of Rocky Linux vs. RHEL should also consider the entities behind the projects: Red Hat, an IBM subsidiary since 2019, is the creator of RHEL, whereas Rocky Linux is owned by the Rocky Enterprise Software Foundation (RESF). RESF describes itself as a "self-imposed not-for-profit" company; while they are not a 501(c)3 or 501(c)6 nonprofit organization, they maintain that their designation as a Public Benefits Company (PBC) is to prevent any one corporation, individual, or group of individuals from having too much influence or control over the project.  

It's also worth mentioning that one of the founders of Rocky Linux is Gregory Kurtzer, who was also a founding contributor of CentOS Linux. When Red Hat acquired CentOS Linux and then discontinued it in favor of CentOS Stream, Kurtzer created Rocky Linux as a free alternative to RHEL, which is what CentOS had been.

Is Rocky Linux Still 1:1 Compatible With RHEL? 

In terms of functionality and features, Rocky Linux and RHEL are virtually identical. Rocky Linux formerly used the RHEL source code to build their own packages (as did AlmaLinux, Oracle Linux, and many others) but Red Hat's move to restrict RHEL source code access changed the method by which they maintain compatibility.

Rocky Linux still maintains 1:1 compatibility, but in a different manner than AlmaLinux and Oracle Linux. In a statement from July 29, 2023, Rocky Linux said it obtains the “source code from multiple sources, including CentOS Stream, pristine upstream packages, and RHEL SRPMS.” 

The table below illustrates how Rocky Linux and RHEL compare when it comes to factors like licensing, security, package management, and support.

Rocky Linux vs. RHEL Cost

At a glance, this is an easy one: As a community-managed distribution, Rocky Linux is free to install and run, so theoretically the cost is zero. RHEL is a commercial product sold by Red Hat, so users pay annual fees that are based on the number of servers (close to $400/server per year as of this writing). 

Calculating the Total Cost of Ownership is a little less straightforward, since it encompasses things like commercial support, hardware costs, complexity, and personnel required to maintain.

Rocky Linux vs. RHEL Packages

Rocky Linux's goal is to be completely compatible with RHEL, like CentOS was. The packages are all compiled from the same sources and patches. One of the few differences is branding. The redhat-* packages are replaced with rocky-* packages, and branding has been changed so that Rocky is present instead. Other than that, anything that can be installed and run on RHEL will be able to be run on Rocky with no changes.

Rocky Linux vs. RHEL Release Cadence and Lifecycle

Rocky Linux releases closely follow RHEL releases, usually by days or weeks. These brief delays are due to the rebuild process and community-driven development. For example, RHEL 9.3 was released on November 7, 2023, and Rocky Linux 9.3 was released on November 20, 2023.

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Rocky Linux vs. RHEL Licensing

Rocky Linux and RHEL have distinct licensing models. Rocky Linux is a community-driven, open source project. It is released under the BSD 3-Clause license, which allows free use, modification, and distribution. There are no licensing or subscription fees associated. 

RHEL is a commercial product from Red Hat and requires a subscription license to use. This is generally based on the number of systems and the level of support needed.

Rocky Linux vs. RHEL Support

Rocky Linux and RHEL offer different levels and types of support.

Rocky Linux doesn’t offer paid support itself. It has community support through forums and documentation. You can also purchase support through third-party vendors like OpenLogic. 

RHEL comes with commercial support directly from Red Hat. This includes technical assistance, access to Red Hat Knowledgebase, and dedicated support channels.

Migrating From CentOS to Rocky Linux

Migrating from CentOS to Rocky Linux is relatively easy, at least from version 8 or 9.  There is no Rocky Linux 7, so you would have to upgrade CentOS 7 to 8 first, then migrate.

There is a conversion script available from Rocky Linux called migrate2rocky.sh. This will migrate from CentOS 8 to Rocky Linux 8. There is another one called migrate2rocky9.sh for migrating from CentOS 8 to Rocky Linux 9.

This script does a bunch of things, but mainly, it replaces the CentOS repos with the equivalent Rocky Linux repos, then replaces a few specific packages, such as replacing centos-release with rocky-release.

CentOS Stream may have some higher package versions than the point releases due to it being a rolling distribution. The script saves the newer version, but disables the repos so any updates come from the current repos. A later point release should replace those as well.

Migrating from CentOS to RHEL

Red Hat has a similar tool called convert2rhel. You do have to have a valid RHEL subscription to do this, though. There is even an instruqt lab that you are able to run that demonstrates migrating a CentOS system to RHEL. It will convert from CentOS to a current fully supported version of Red Hat.

Choosing Between Rocky Linux and RHEL

There are several factors to consider when choosing between Rocky Linux and RHEL. Cost and support are probably the two biggest considerations. RHEL is not free, but the license includes 24/7 technical support from Red Hat, along with updates and patches.

Updates and patches for Rocky Linux are provided by the community, but without enterprise-grade, SLA-backed support. The community does not have SLAs, for example, so you may not get a fix or support for a problem in a time period that works for you or your customers. This is why some organizations may find it necessary to pair Rocky Linux with a commercial support offering, to ensure that any issues are addressed quickly.

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OpenLogic helps organizations enjoy the benefits of a free and open source Enterprise Linux distribution without the risk. Our team includes experts who are directly involved with the Rocky Linux project.

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Additional Resources

• Blog - How to Find the Best Linux Distro for Your Organization
• Blog - Rocky Linux vs. AlmaLinux
• Video - What's Next for Rocky Linux
• Webinar - Exploring the Post-CentOS Linux Landscape
• Blog - Top Enterprise Linux Distributions from the State of Open Source Report 
• White Paper - Decision Maker's Guide to Enterprise Linux