As RHEL clones hit version 10, Rocky and Alma chart diverging paths

Rocky Linux 10 has caught up to the other high-profile RHELatives, but gaps between them are widening, both in tech and other ways.

Rocky Linux 10 "Red Quartz" has reached general availability. The release notes describe what's new, such as support for RISC-V computers. Balancing that, this version only supports the Raspberry Pi 4 and 5 series; it drops Rocky 9.x's support for the older Pi 3 and Pi Zero models.

"Red Quartz" follows AlmaLinux 10 "Purple Lion", which arrived at the end of May. That was just a couple of weeks after RHEL 10 landed, which as we covered at the time, was very quietly released just before the Red Hat Summit in mid-May.

Since the IBM subsidiary killed off CentOS Linux at the end of 2021 and made some of RHEL's source code much harder to get at, it has been replaced with a new generation of slightly different products. Now, years later, these are taking on their own identities and gradually differentiating themselves from RHEL itself, and from one another. With the advent of the RHEL 10 release, some of those differences are becoming more apparent. We will try to summarize the growing divide.

Two of them we won't go into directly here. CentOS Stream 10 came out ages ago, and at the time of writing, Oracle Linux 10 isn't out yet. We described the big technological differences between RHEL and Oracle Linux when Oracle released version 9. Oracle offers its own optional Unbreakable Enterprise Kernel, which is much newer than Red Hat's version and includes Btrfs support.

The technological differences

As covered in the AlmaLinux 10 release notes, perhaps the biggest and most obvious technological difference in this version is that AlmaLinux offers a separate version for x86-64-v2 hardware.

RHEL 10 itself, and Rocky with it, now require x86-64-v3, meaning Intel "Haswell" generation kit from about 2013 onward. Uniquely among the RHELatives, AlmaLinux offers a separate build of version 10 for x86-64-v2 as well, meaning Intel "Nehalem" and later - chips from roughly 2008 onward. AlmaLinux has a history of still supporting hardware that's been dropped from RHEL and Rocky, which it's been doing since AlmaLinux 9.4. Now that includes CPUs.

In comparison, the system requirements for Rocky Linux 10 are the same as for RHEL 10. The release notes say:

Trying out RHEL's unique feature: an LLM bot

A significant element of the advertising around RHEL 10 involves how it has an AI assistant. This is called Red Hat Enterprise Linux Lightspeed, and you can use it right from a shell prompt, as the documentation describes. The command is called simply c - as the docs say:

The Reg FOSS desk is a confirmed AI skeptic, as regular readers may have worked out - for instance from our story on Gentoo and NetBSD banning AI code. Even so, we were curious about this and wanted to have a cursory look.

We expected to find it in the Cockpit web management interface - which is like Webmin for the 21st century - but there isn't a trace we could see in there. In fact, it's an optional shell command.

This version is in a package called command-line-assistant, whose description reads: "A simple wrapper to interact with RAG." In the LLM field, that stands for retrieval-augmented generation and The Reg has touched upon this before, including how to try it for yourself. In theory, it results in more accurate output that's constrained to the contents of a supplied database like product documentation.

In the old days of boxed Linux distributions, SUSE used to be famed for the quality of the documentation it provided. The company still has a substantial team of "documentarians" writing manuals, but Red Hat has a rather larger one, and has excellent docs available to its customers. (This vulture speaks from personal experience: he has in the past been a member of both teams.)

The assistant is a modest install. The packages were only a 4.2 MB download and took 24 MB of disk space. The default desktop installation only took 4.4 GB of disk space, which isn't especially large by 2025's abysmal standards in this department.

Querying it is quite slow. For instance, we tried:

The bot displayed a twinkling prompt:

(The plus symbols are animated by replacing them with some other symbol, too fast to read. It's slightly more twee than we expected from an enterprise Linux distro, but hey, we're old and grumpy.)

After it chugged for a few seconds, it responded with a screenful of text explaining the df command and how to use it, with examples.

Much as we'd like to, at this level, we can't really fault this. It's much easier than searching man pages, especially if you don't know what to look for. Everyone started out as a rookie once, and to a managerial type, typing anything at a command prompt like this looks like serious tech wizardry. If it helps you become such a wizard in time, that's great. The assistant doesn't seem to execute commands for you, or return real information about your machine, but it gives you commands that you could copy-and-paste into a live terminal.

That said, though, it wouldn't be hard to get into a mess.

We asked the bot how to enable the EPEL repositories and it gave us instructions for RHEL 9, with a passing mention that you might have to change the relevant version number.

We asked it how to install and enable Cockpit. Rather than telling us "Cockpit is already installed and enabled by default in RHEL 10," it proceeded to give us a set of instructions. We tried to follow them, and the process threw some errors, as it was already there. But, to the tool's credit, nothing broke.

"Vibe administering" a RHEL server in production will not go well, and if a newbie PFY blindly copies and pastes such output, they are heading very quickly toward contributing a future Who, Me? story. But considered more as training wheels for a console jockey, it could have its uses. From this vulture, that is very high praise.

How big?

The RHEL 10 ISO file is a substantial 8.5 GB in size. Initially, we thought that the large download might be due to a bundled LLM bot and its statistical database, but it's not that. The Lightspeed tool depends on an online service provided by Red Hat itself, and it won't work without an active internet connection. As this implies, neither AlmaLinux 10 nor Rocky Linux 10 includes the option of a helper bot. No big surprise there.

They are both still big downloads, though. The Rocky Linux 10 ISO and AlmaLinux 10 (for x86-64-v2) are both over 7 GB - so about a gigabyte smaller. All three are even bigger than the conspicuously pudgy Ubuntu Plucky.

We're not sure why their downloads are so big, because once installed, RHEL 10 takes about 4.4 GB of disk space. In other words, it's about half the size of its own installation media. Both Rocky and Alma 10 are similar in installed size. Rocky 10 is a few hundred megs smaller, and Alma 10 a few hundred bigger - but we did have to manually install the supporting infrastructure for VirtualBox's guest additions.

All three use kernel 6.12, and come with GNOME 47, running on Wayland. All three use about 1.2 GB of RAM at idle, but then, GNOME is not a lightweight desktop. All three come with Cockpit pre-installed and running in the background. But then, you'd expect all the RHELatives to be similar. That remains their primary selling point.

Looking at the fine print

However, there are other, non-technological differences between them. One of the selling points of RHEL and SUSE SLE is not so much technical as legislatory. Red Hat maintains compliance with various government and industry standards.

A slow stream of announcements indicates that both CIQ (Rocky's corporate backer) and some of AlmaLinux's partners seem keen to acquire some of these quite expensive bits of paper that soothe the furrowed brows of finance directors.

Recently, TuxCare announced live patching of kernel vulnerabilities, part of its enterprise support for AlmaLinux, which also includes US government FedRAMP security. TuxCare also offers security hardening for AlmaLinux. AlmaLinux 10 is a little too new to be covered just yet, though. At present, these offerings are for versions in the 9.x release series.

Comparably, CIQ now offers a special version of Rocky Linux, called Rocky Linux from CIQ - Hardened, or RLC-H for short. This launched at the start of the month and follows CIQ's announcement of FIPS 140-3 compliance. Back in May, CIQ also announced an AI-optimized version, and the month before that, tools for HPC cluster administration.

In summary, as they mature, the most visible of the RHELatives all remain very similar distributions, but they are very slightly diverging in small ways as they adapt to slightly different positions on the market.

In February, The Reg FOSS desk attended the CentOS Connect conference, and it was quite a small affair. We do not hear or see much about CentOS Stream usage in Linux forums online, but even if Meta is its only user, that's a big and important one.

A surprise from the Ubuntu Summit 2024 was the high level of Rocky usage. It's sticking closest to upstream, thanks to a clever loophole to obtain source RPMs. Its hardware requirements also closely parallel RHEL 10, and CIQ is working on certifications, compliance, and special editions.

Meanwhile, AlmaLinux is maintaining support for older hardware and CPUs, which will widen its appeal, and working with partners to ensure reboot-free updates and patching, rather than CIQ's keep-it-in-house approach. All are valid, and all three still look and work almost identically... except for the LLM bot assistant. ®

Bootnote

We feel we have to go with the industry flow when it comes to talking about the different revisions of the x86-64 instruction set, which we described when SUSE gave it relevance.

As we said when talking about the AlmaLinux and RHEL 10 betas, the paramount penguin-herder himself, Dr Torvalds, disdains the terminology - but it's rapidly becoming the industry standard. Sorry, Linus.