Oracle releases experimental next-gen kernel build

UEK-next is bleeding edge – unlike most CentOS-alikes

Oracle's Linux engineers have released their build of kernel 6.9 for Oracle Linux – and they're already planning for 6.10 and beyond.

In April, Oracle updated its own kernel build for Oracle Linux, the UEK-next kernel, which is a continuous integration Linux kernel release. This has just borne fruit in the form of a new release, UEK-next 6.9. It's based on the very latest stable kernel release 6.9 released in May.

This is not your typical enterprise Linux distro kernel. Indeed, its release notes specify:

UEK-next is not supported for production use, however we will provide limited test and development support for these kernels to help validate applications and workloads.

In 2022, when Oracle Linux 9 came out, we took a look at some of its differences from other CentOS Linux-based distros. Notable among these is that Oracle offers a choice of two different kernels: RHCK, its Red Hat Compatibility Kernel; and UEK, the quite different Unbreakable Enterprise Kernel, which it has been offering since 2010.

Oracle explains that "the UEK-next release is built by applying UEK specific fixes on top of the latest Linux mainline release tag." It also describes that configuration and how it differs from the upstream kernel. Differences include its soft affinity feature, which it first offered upstream in 2017 and then again in 2019.

Notably, the UEK offers Btrfs – a file system for which Red Hat itself dropped support way back in 2017.

Oracle includes other features that haven't made it into the mainline kernel yet – such as the ability to change the kernel scheduler using the "pluggable scheduling framework" sched_ext, which is built on the eBPF kernel programmability feature. At present, this is being considered for inclusion in kernel 6.11.

In other words, the version after next. Right now, kernel 6.10 is still work-in-progress, and is only at release candidate 6 stage. This is some cutting-edge stuff, and shows that UEK-next isn't simply a bunch of vendor-specific tweaks to the upstream kernel 6.9 – it has some quite major differences.

Even for this jaded old vulture, it feels overly cynical to describe this as Oracle flexing its muscles. The database champ has been maintaining its own distro since way back in 2006 and the following year denied that it was intending to fork RHEL. It has clearly gathered significant expertise in that time, which it can now contribute to the OpenELA initiative it co-founded last year. ®

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