[CentOS-devel] https://blog.centos.org/2020/12/future-is-centos-stream/

Wed Dec 9 20:48:56 UTC 2020
Phil Perry <pperry at elrepo.org>

On 09/12/2020 19:01, Brendan Conoboy wrote:
> On Wed, Dec 9, 2020 at 10:04 AM Phil Perry <pperry at elrepo.org 
> <mailto:pperry at elrepo.org>> wrote:
> 
>     On 09/12/2020 17:40, Stef Walter wrote:
>      > On Wed, Dec 9, 2020 at 6:33 PM David Hrbáč <david-lists at hrbac.cz
>     <mailto:david-lists at hrbac.cz>
>      > <mailto:david-lists at hrbac.cz <mailto:david-lists at hrbac.cz>>> wrote:
>      >
>      >         I don't use CentOS Stream, I use RHEL. I use RHEL to develop
>      >         software
>      >         for RHEL and compatible OS clones, including CentOS. If
>     Stream
>      >         retains
>      >         binary compatibility, and specifically kernel ABI
>     compatibility,
>      >         then
>      >         the users of the software packages we develop can continue to
>      >         use them.
>      >         If not, they can't. Simple as that. So please don't push
>     rolling
>      >         kernel
>      >         updates to Stream that break the kernel ABI.
>      >
>      >
>      > Indeed. If any such broken change (eg: that breaks kernel ABI) is
>     pushed
>      > to Stream, that is treated as a serious problem by the RHEL
>     engineering
>      > teams. We have the necessary process in place to QE test changes
>     before
>      > they arrive in CentOS Stream.
>      >
>      > I understand this fact alone is not a panacea for all the problems
>      > people are highlighting. But it does seem to cover your use case.
>     From a
>      > regression, stability, ABI, and kernel ABI perspective, it is the
>     goal
>      > and focus of many of us in RHEL Engineering for CentOS Stream to
>     be stable.
> 
>     Hi Stef,
> 
>     Thank you for your response. You do realise I'm not just talking about
>     whitelisted kernel symbols, but the whole kernel ABI?
> 
>     Whilst the RHEL kernel ABI whitelist is great in principle, in practice
>     I am yet to find a kernel driver that uses only symbols on the
>     whitelist. As I said previously, every single driver I maintain broke
>     between RHEL8.2 and RHEL8.3 due to changes in the kernel ABI.
> 
> 
> Yes, the symbol list is helpful, but it's rarely 100%, so we're going to 
> have to iteratively do better.
> 
> Just to be clear, I don't think this is your job or David's job to 
> solve, just knowing that if we collectively solve it, it makes CentOS 
> Stream a more viable option for you and others was the insight I was 
> hoping for.  There are probably many of these, but this is the one I'm 
> hearing repeatedly in this thread.  In the months ahead there are going 
> to be numerous, uh, "opportunities", to solve these sorts of things 
> together :-) If the kind of thing you can bring is what does and doesn't 
> work for you and why, I'll take it.
> 

Great. Once kernel-4.18.0-257.el8.x86_64 makes it into Stream, I'll be 
happy to test and feed back. Any ETA on that? I see it was built a week 
ago on koji