Proxmox 9 Kernel and Ubuntu 25.04?

SInisterPisces

SInisterPisces

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Sep 1, 2022
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Hello,

Linux kernel 6.12 was announced to be 2024's LTS kernel this week; that got me thinking about this.

I just wanted to to check and see if I actually understand how Proxmox integrates Linux kernels now, as I used to be pretty confused about it. I think PVE major releases are tied to Ubuntu kernel releases, so I think it'll be based on the Ubuntu 25.04 kernel (6.14, see: https://www.phoronix.com/news/Ubuntu-25.04-Early-Plans ). Is that correct?
 
Proxmox is based on Debian (Proxmox 8 is based on Debian 12)

Debian 13 should be released this year, and will use kernel 6.12 LTS. I expect Proxmox 9 to be based on Debian 13.
 
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See: https://pve.proxmox.com/wiki/Proxmox_VE_Kernel

@Freeben As @BobhWasatch notes, Proxmox's default kernel is a modified Ubuntu LTS kernel, and the Debian repositories are only used for userspace (non-kernel things you install from the repos). So, Proxmox 9 (or 8.future if things get interesting) will ship with the Ubuntu 25.04 kernel, kernel 6.14, and will only jump to a newer major kernel version (6.15, etc.) if/when Ubuntu 25.04 does.

The experimental kernel, I believe, tracks Ubuntu's non-LTS releases.
 
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How are people doing with this 6.14 kernel in May 2025? I'm tempted to try it, but seems like it might be a bit of a rough ride still.
 
You're using a very reliable package from one vendor and want to tweak the kernel as well? How does that come about? Pure playfulness? Too much time? Are you a kernel junkie? I'm asking for a friend.
 
72cpus said:
Ubuntu 25.04 is not an LTS release.
Click to expand...
Right you are. I misspoke on that one. I always goof up some part of this when I try to talk about it.

Let me try again to make more sense. Referencing this: https://ubuntu.com/about/release-cycle

Ubuntu kernel release cycle​


Canonical maintains multiple kernel packages for each LTS version of Ubuntu, which serve different purposes. Several of the kernel packages address the need for kernels with specific performance priorities, for example, the low-latency kernel package. Others are focused on optimisation for a particular hypervisor, for example, the kernel packages which are named after public clouds. You are recommended to use the detailed Ubuntu kernel guide to select the best Ubuntu kernel for your application.


In general, all of the LTS kernel packages will use the same base version of the Linux kernel, for example, Ubuntu 20.04 LTS kernels typically used the 5.4 upstream Linux kernel as a base. Some cloud-specific kernels may use a newer version in order to benefit from improved mechanisms in performance or security that are material to that cloud. These kernels are all supported for the full life of their underlying LTS release.


In addition, the kernel versions from the subsequent four releases are made available on the latest LTS release of Ubuntu. So Ubuntu 18.04 LTS received the kernels from Ubuntu 18.10, 19.04, 19.10 and 20.04 LTS. These kernels use newer upstream versions and as a result, offer an easy path to newer features and newer classes of hardware for many users of Ubuntu. Note however that these kernels ‘roll’ which means that they jump every six months until the next LTS. Large scale deployments that adopt the ‘hardware enablement’ or HWE kernels should manage those transitions explicitly. These newer HWE kernels are accompanied by a collection of userspace tools closely tied to the kernel and hardware, specifically X11 display enablement on newer graphics cards.
Click to expand...

So, the Ubuntu LTS releases do get newer kernels before the next Ubuntu LTS release.
Referencing this from the Kernel 6.14 thread: https://forum.proxmox.com/threads/o...e-8-available-on-test-no-subscription.164497/
We recently uploaded a 6.14 kernel into our repositories. The current 6.8 kernel will stay the default on the Proxmox VE 8 series, the newly introduced 6.14 kernel is an option.
The 6.14 based kernel may be useful for some (especially newer) setups, for example if there is improved hardware support that has not yet been backported to 6.8.
This follows our tradition of upgrading the Proxmox VE kernel to match the current Ubuntu version until we reach an (Ubuntu) LTS release, like the 6.8 kernel is, and then provide newer kernels as opt-in. The 6.14 kernel is based on the Ubuntu 25.04 Plucky release.
Click to expand...

That bolded part there is the part that confuses me. So, Proxmox updates the kernel to match the current Ubuntu version until an Ubuntu LTS is released, pins that kernel, and offers newer kernels as opt-in?

That makes sense to me, but Ubuntu 24.04.2 LTS (HWE) lists kernel 6.11 as the default there. But, the testing repos for PVE are using 6.14.

So, taking all that into account, I've realized that I still don't really know how to predict which kernel version will be the next non-testing one for Proxmox 9 … though I suspect Proxmox 8 will remain on Ubuntu LTS kernel 6.8, if I'm reading that right.
 
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