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Comment by sheepdestroyer | Hacker News Reader

Can you explain in what case being exactly bug for bug compatible with a given set of RedHat rpms (which are also in flux all the time with regular updates) is actually more important to you than having less bugs in total?

I understand that if your goal was to use CentOS to validate a specific and highly critical workload for eventually running in production on Redhat systems (taking into account the version lock dance to make sure that you indeed have the exact same package versions on both environments, meaning a lot more hassle and delays in bug fixes and security updates that simply following the regulars updates), then Rocky/Alma/AnyRebuild will be better for you.

If your goal was already to run production on CentOS, with frequent updates for security, the theory would be that you will be even better served by CentOS Stream. My take is that it is the most popular case.

What am I missing?

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CentOS Stream is a "rolling release" that's serves a specific purpose of being bleeding-edge test environment to test new changes for future integration into RedHat's stable releases.

Many high-availability workloads require a fixed operating-system baseline, where the only changes are security updates and high-priority bug fixes.

And even these changes may need to be triaged to determine if the updates are even worth risking uptime.

One example would be a hospital network with medical equipment workstations and backend servers. You don't want your ultrasound or key-hole surgery not working because a CentOS Stream update bug. Fixed operating baselines are important for many users.

On the linux front, I've used a mixture of RHEL/CentOS/Ubuntu for about the last 10-15 years, so the whole CentOS thing was a bit of an annoyance, but I gave the CentOS Stream side of things a go.

And I'd probably describe it as less of a "bleeding-edge" rolling release, more a "boring-edge" rolling release. Yes it's a rolling release, but packages are going in as a final shakedown before release into RHEL, so it's really quite far away from experimental.

And I've not really noticed any material difference from pre-stream. I'm still able to use my CentOS boxes in the same way as I did before - in some cases as build boxes for things to be deployed onto RHEL boxes.

(And, to be honest, those example use cases are probably places where I would be seeking to use a commercially supported distribution, rather than a community supported one. Albeit a community supported distribution that copies/replicates a commercially supported distribution.)

But this is not the case as I understand it.

From RedHat's announcement blog and Centos website: CentOS Stream "a continuously delivered distribution that tracks just ahead of Red Hat Enterprise Linux".

And indeed, I have read that all packages currently going into Stream 8 follow exactly the same testing and validation procedures than for entering Redhat Proper.

But of course, this holds true only for released RedHat versions. Meaning that Stream 8, is currently just ahead of RedHat 8.5 and will soon start to incorporate changes planned for 8.6 (so nothing like a "bleeding-edge test environment to test new changes" as you put it).

As for Stream 9 which was release recently, it is indeed the stabilisation socle based on fedora 34 that will eventually become RedHat 9. Once RedHat 9 released, Stream 9 branch will be stabilized and once again be "just ahead" of the impending RedHat 9 rpms.

In any case, I am not sure that hospitals should be running/updating self supported OS on surgical equipments without proper testing anyway.

> As for Stream 9 which was release recently, it is indeed the stabilisation socle based on fedora 34 that will eventually become RedHat 9. Once RedHat 9 released, Stream 9 branch will be stabilized and once again be "just ahead" of the impending RedHat 9 rpms.

Stream 9 is currently tracking RHEL 9.0, it shifted from the 9.0 Beta back around August. As we approach the ~May release for RHEL 9.0 GA, Stream 9 will start tracking RHEL 9.1 changes.

A key difference between Stream 8 and Stream 9 is the way the distribution is built. Stream 8 is a technically another rebuild project by the CentOS team, but one that rebuilds newer branch packages from RHEL engineering. In Stream 9, RHEL engineers are doing the builds themselves and are directly involved in the entire process.

There's a possibility that Stream 8 may adopt the Stream 9 workflow, but I'm not certain. With an EOL of 2024, it might not be considered a priority.

It would be the medical equipment manufacturer who would choose CentOS. And I'd argue CentOS was a fine choice given its track record and RedHat sponsorship.

Don't those installations tend to use a commercially supported distribution (RHEL in this particular case)? I've never worked on anything similar but find it really hard to believe you'd go around installing a "community enterprise" distribution on critical infrastructure.

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