I work for Oracle on their cloud platform (including reasonably closely with the Oracle Linux team, as my team is responsible for the main platform images).
Speaking entirely for myself, opinions my own, may not reflect my employer etc. etc:
I came in to this job expecting OL to just be a CentOS clone, and not really expecting much from the kernel they ship with it.
It is both a CentOS clone, and a bunch more. Oracle takes the CentOS packages and applies bug fixes etc. that upstream RedHat has failed or refused to apply, so I've actually found OL to suffer from fewer problems than CentOS, and we've even had to apply mitigations for CentOS 6 for stuff we haven't had to do to any other OS we distribute. For entirely selfish reasons, I was really glad to see CentOS 6 go end of life last month.
On top of that the OL team hires a significant number of upstream kernel developers, including the core maintainers for a number of components, like XFS, Xen, and so on, and produces the Unbreakable Enterprise Kernel (a really curious choice of marketing terminology), that incorporates mainstream bug and security patches, while being closer to mainstream than RHEL/CentOS, and the kernel patches submitted upstream by OL devs.
Should be. It's CentOS packages with rebranding and maybe some custom fixes on top. There are two kernels that ship with it, either the RedHat Compatibility Kernel (RHCK), or the Unbreakable Enterprise Kernel (UEK).
I would point out, I'm not in the OL org, I have absolutely no idea what this change means for Oracle Linux. Oracle Linux is based off the CentOS sources as that's the only way that RedHat was making the source code to their distribution available (there way of meeting the terms of the GPL). RedHat has to make their source code available in one form or another so I can't imagine that this would have any impact on OL, but that's entirely guess work.
I didn't know Oracle builds from CentOS rather than RHEL sources. Nor that RHEL doesn't release sources anymore?
If that's true, I wonder how Oracle got some of their 8.x releases out much earlier than CentOS. (Oracle Linux 8.3 2020-11-13 vs CentOS 8.3 2020-12-08, Oracle Linux 8.0 2019-07-19 vs CentOS 8.0 2019-09-24.) I'm assuming here without verification that both track the RHEL 8 point releases.
if i remember correctly, RHEL source dumps always lacked some machinery to actually produce a working release; that’s where CentOS were doing actual work, painstakingly replicating all the compilation quirks to end up with RPM builds that matched RHEL. That’s likely why another clone might want to start from CentOS rather than RHEL sources.
I can't speak to that. I'm not in the OL team and don't know what they do / did. Oracle can/does throw a lot more engineers at development and build than CentOS does (I believe they only have a few engineers). I believe the stuff for building the RPMs lands in the CentOS git repo early on.
