Why Centos still not using Latest kernel

Question

As i have seen many changes and improvement in kernel 3.xx

The improvement i like is dmcache which introduced in kernel 3.9

I have 3 server with centos installed on all machine

Centos is still using old kernel which is 2.6.xx

I'm wondering why they are not upgrading kernel?

Resources

• Kyle Manna's blog about linux's dm-cache

• dm-cache (Wikipedia)

• Centos (Wikipedia)

Solution 1

CentOS 6 is based on RHEL 6, which was released in 2010. Within a major release, the goal is compatibility and not introducing breaking changes as the target audience is enterprises that value stability over features. As you can see from the version history, they don't introduce new kernel versions within a major release (but some fixes are backported), so it's likely RHEL 6/CentOS 6 will stay on 2.6.32 (a stable kernel version).

To get a newer kernel, you'll have to wait for RHEL 7/CentOS 7 and upgrade. It will include kernel 3.10 (another stable kernel release).

Since Red Hat supports each release for 10 years (or 13 with extended support, e.g. RHEL 6 until 2023), it's no surprise they don't release a new major version every year.

Solution 2

There may be a disconnect here.

CentOS, like any enterprise linux, is geared toward stability and, importantly, compatibility throughout the major release (review Semantic Versioning).

In order to maintain compatibility, software released within a given major release will not suddenly be revised to a completely different baseline. In addition to breaking any kind of certification in the upstream distro (RHEL) with ISVs, the nightmares in (in order) testing and then support will create an untenable labour issue for anyone trying to actually support it.

If you need last week's code drop, you may want to consider a project with a release cycle more like a mayfly and less like infrastructure. Your upstream and downstream support will change dramatically, and consistently delivering a product may become a moving target, but this may be a great experience. Maybe look at this month's Fedora, or whichever mubuntian deriv is fashionable.

EL8 will of course have a newer kernel, and you may want to use Fedora in your test environment so that you can properly release on EL8 when Fedora's promoted to EL.

Comments

[CharlieRB]

Please be aware you have posted an answer to a question that is very old and has an accepted answer. Although there is nothing wrong with doing so, just be aware you may not get a response.

[user2066657]

Yep. Couldn't respond to the 'middle of 2015' comment but it's a constant question from people who just don't get it. Just like Einstein was really bad at being a fish, Enterprise Linux distros are really bad at staying stable and compatible throughout their lifespan if they gobble up this week's release. It's the obvious nature of the logic that drives me.

[Stefan Lasiewski]

If you do want to track the latest Linux kernel, there are operating systems that track it, and you'd be better off following an alternative instead of customizing CentOS. See wiki.ubuntu.com/Kernel/MainlineBuilds for one such example.