Re: CentOS and Debian/Ubuntu release cycles
On Wed, Dec 09, 2020 at 04:25:54PM +0000, Stephan Lachnit wrote:
> Hi all,
>
> maybe you already have heard it, CentOS is basically dead now. It used to be an exact RHEL clone, but now it's kind of an RHEL beta [1].
>
> Now what does that have to do with Debian?
>
> When we look into why people use CentOS, the reason is pretty simple: it is (or was) binary-compatible with RHEL, just without the support [2].
> I was reading comments from people that use RHEL on their production, but CentOS at home or for testing, because you don't need to pay for it.
> These use cases now don't work anymore, forcing them into either paying for RHEL, or moving to a different ecosystem.
>
> The more I started thinking about it, the more I wondered about why Debian Stable and Ubuntu LTS are *not* binary-compatible.
> It just doesn't make sense to me. Both Debian Stable and Ubuntu LTS provide a more "long term" approach than let's say Fedora.
> And while Ubuntu LTS is based on Debian, it is not based on Debian Stable, even though they have release cycle of two years.
> It would seem kinda obvious that Debian and Ubuntu have a common freeze period and work on LTS maintenance together.
>
> Does anyone know why this is not the case? I suspect some historical reasons, but I couldn't find anything quickly.
>
> - Stephan
>
> [1] https://blog.centos.org/2020/12/future-is-centos-stream/
> [2] It's easy to find comments on various blogs or social media, but for sake of completeness let me just mention that CERN [3], [4].
> [3] https://linux.web.cern.ch/centos/
> [4] https://linux.web.cern.ch/other/
>
Two different distributions: two different approaches. Ubuntu support a small
subset of packages in their main distribution (as opposed to
multiverse/universe). Ubuntu packages are often pulled from Debian stable and
testing at the same time, brought together and then released. Ubuntu changes
significantly every six months and publishes an LTS once every two years.
Debian releases when it's ready. Support is generally two years plus a year after the next version. There is now an LTS extended support after that
period for a further two years and maybe even ELTS after that. That's support
provided by Debian developers who are paid for their time.
Ubuntu and Debian may be >90% compatible but have a subtly different approach
to bundling non-free firmware / compilation options or other differences.
Derivative distributions diverge further, of course.
Ubuntu questions are often considered off-topic on Debian lists - we may not
have exact expertise - and vice versa.
Hope this helps
Andy C.
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