You may have heard about AlmaLinux and Rocky Linux as alternatives to CentOS now that Red Hat has shifted focus from CentOS to Stream. But how exactly do these two enterprise Linux distros differ? Which one is right for your business needs?

This article examines the key similarities and differences to consider.

An Overview of the Rocky and AlmaLinux Backstories

First, some background. The CentOS community was shaken up when Red Hat announced plans to discontinue CentOS Linux in favor of CentOS Stream. CentOS Stream is essentially a rolling release distro that provides early access to future enterprise Linux features.

Many companies relied on CentOS as a free, enterprise-grade platform. So two new projects quickly formed to fill the void:

• Rocky Linux - Launched by Gregory Kurtzer, the original founder of CentOS, with contributors from the CentOS community. The intent is to function as a downstream build of Red Hat Enterprise Linux (RHEL).

• AlmaLinux - Formed by CloudLinux, a commercial company known for Linux server OS products. AlmaLinux aims to be a 1:1 binary compatible with RHEL.

Both distros promise long-term support for enterprise workloads, unlike the shifting nature of CentOS Stream. But there are some key differences too.

Release Cycles and Long-Term Support

A core difference is how Rocky Linux and AlmaLinux handle releases and long-term support.

Rocky Linux follows a traditional CentOS-style approach. It provides a new minor release approximately every 6-12 months. Each release gets at least 5 years of support. For instance, Rocky Linux 8 will receive updates until at least 2026.

AlmaLinux adheres to RHEL's 10-year lifecycle model instead. So AlmaLinux 8 promises coverage until 2029 rather than just 2026 for Rocky. The trade-off is less frequent releases - a new minor version every 2-3 years rather than annually.

For most enterprise use, AlmaLinux's longer guaranteed support may be preferable for minimal upgrade disruption. But Rocky offers more flexibility for those wanting newer components at a quicker pace.

Philosophy and Community Governance

There are also philosophical differences that could sway your choice:

Rocky Linux is a community-driven, grassroots project launched by the original CentOS founder. It stands by the community-centric ethos of CentOS with fully open development and transparency. The project states that "The governance is by the contributors, transparency by default."

AlmaLinux has corporate backing from its inception by CloudLinux. So it offers perhaps more structured processes. But AlmaLinux also emphasizes a community orientation and that development occurs "in the open."

In terms of community activity so far, Rocky Linux probably has an early edge given community ties and Kurtzer's reputation. But with corporate resources, AlmaLinux may be positioned to scale up quicker. Over time, both likely can thrive with community involvement.

Compatibility and Hardware Architecture Support

As downstream rebuilds of RHEL, Rocky and AlmaLinux naturally aim for high compatibility:

• Application compatibility - All three support Red Hat compatible userspace such as yum and popular packages like Apache or MariaDB. Any software certified for RHEL should run on Rocky or AlmaLinux. But Rocky had a head start in testing many top open-source apps.

• API/ABI compatibility - Both distros adhere to RHEL kernel APIs and ABI stability requirements for more seamless compatibility.

• Certification compatibility - Many ISVs plan to offer support and certify the distros for their commercial software. For instance, Microsoft has committed to support Rocky on Azure.

On hardware architecture support, Rocky supports x86-64 while AlmaLinux adds both aarch64 for 64-bit ARM and ppc64le for POWER platforms.

So if app or hardware support is critical, review specifics closely on needed compatibility. But the roadmaps are reasonably well-aligned.

Installation and Administration Experience

As downstream rebuilds, all three distros provide the familiar RHEL/CentOS administration environment:

• Installation - The installers will be very similar as Anaconda is used across the board. But some fine-tuning differences may arise.

• Package management - Yum/DNF manages RPM packages consistently across the platforms.

• System configuration - Administration staples like systemd, firewalld and chkconfig is universally present. So skills transfer directly from existing RHEL/CentOS know-how.

For hands-on admin experience, there should be minimal adjustment pains when switching between the options. The flow will remain intimately familiar either way.

Evaluating Your Needs

With the background covered, how do you evaluate AlmaLinux vs Rocky Linux for your needs? Here are some key questions to consider:

• Do you require a 10-year lifecycle support model or content with 5-6 years between upgrades? AlmaLinux provides that extra peace of mind.

• Is community or corporate backing more important? The community spirit may lean towards Rocky but AlmaLinux offers commercial assurance.

• What hardware platforms require support? If 64-bit ARM or POWER systems are needed, AlmaLinux has an edge currently.

• Will certification for specific ISV software influence the decision? Review program specifics as vendors pledge L3 support.

• Does early adoption of new features matter or is stability first? CentOS Stream provides earlier feature exposure while the other two prioritize stability through downstream rebuilding.

Most importantly, take advantage of available trials and testing environments. Evaluate technical fit with your deployment requirements and environment integrations. Minor differences can take precedence based on your enterprise infrastructure needs and what provides the best uplift potential from CentOS 8.

The Future Looks Bright for Both Distros

While uncertain initially after the CentOS shift, the future looks bright for Enterprise Linux. AlmaLinux and Rocky Linux both offer credible options to fill the community-oriented, downstream RHEL ecosystem gap.

The competition should also spur additional innovation in the space. We can expect polished distros fine-tuned to the needs of demanding enterprise production workloads.

Conclusion

Overall both Rocky Linux and AlmaLinux are shaping up as robust platforms for enterprise needs. As the options continue maturing with battle-tested reliability, the choice may come down to personal preference based on support timelines, hardware needs, community affinity or corporate assurances.

So try out each distro to gauge the best fit based on your technical and organizational requirements. The flexibility now allows mixing components like Rocky's faster upgrades or Alma's longer lifecycles to tailor an optimal enterprise Linux foundation for your evolving infrastructure growth.