[elrepo] Announcement: EL7 Updated kmod-nvidia package for RHEL7.6

[Phil Perry]

On 18/11/2018 20:35, Phil Perry wrote:
> <snipped>
> 
>> On 2018-11-09 2:07 a.m., Phil Perry wrote:
>>>
>>> We have been looking at technical solutions to this issue for a long 
>>> time. I
>>> tried to write a yum plugin to prevent yum offering packages where the
>>> prerequisite kernel requirements could not be met, but unfortunately 
>>> my python
>>> skills are not quite up to the job (we would welcome contributions 
>>> here from
>>> anyone with python experience).
>>>
> 
> OK, I've had some success in writing a yum plugin which I've uploaded to 
> the elrepo-testing repository (should be available shortly) for folks to 
> test:
> 
> yum-plugin-elrepo-7.5.0-1.el7.elrepo.noarch.rpm
> 
> Code is available here:
> 
> https://github.com/elrepo/packages/tree/master/yum-plugin-elrepo
> 
> 
> Lets first define the issue we are trying to solve:
> 
> At point releases, some kmod packages require rebuilding against the 
> latest RHEL kernel. The resulting kmod packages *Require* the new RHEL 
> kernel. This can cause dependency errors in yum when clone distros such 
> as CentOS and Scientific Linux have yet to catch up and release their 
> corresponding point release kernels.
> 
> This plugin determines the kernel a kmod package is built against, and 
> will exclude (hide) it from yum if the corresponding kernel is not (yet) 
> available. Once the corresponding kernel becomes available, so will the 
> kmod package(s) that require it.
> 
> However, there is one issue here, due to a major difference between the 
> way yum works on RHEL and it's clones. On RHEL, *all* previous kernels 
> are available to yum. This is not the case by default on CentOS, where 
> only kernels from the current point release are available.
> 
> Consequently, the plugin as described above would exclude (hide) from 
> yum any kmod package built against an earlier kernel (e.g, 7.0) that 
> remains compatible as the plugin can not find the required earlier 
> kernel version on CentOS (and SL?). This is obviously not the intention.
> 
> The solution to this is either:
> 
> 1. set up your repos to mimic how RHEL works, i.e, make all kernels 
> available to yum, or
> 
> 2. for now, I have temporarily excluded all older kmod packages, as 
> identified by their dist tag (e.g, el7.elrepo, el7_4.elrepo, 
> el7_5.elrepo) as we are really only interested in packages for the new 
> point release (currently el7_6.elrepo).
> 
> In the future I may deprecate/remove this feature so the plugin will 
> only work (correctly) if all kernels are available, but I'd like some 
> discussion about how best to handle this. I believe option (1) is more 
> robust than any fudge / workaround I can implement and will allow the 
> plugin to work seamlessly going forward, including on unsupported setups 
> where people have stayed on older point releases. It doesn't matter 
> whether we are talking now, transitioning from el7.5 to el7.6, or 6-12 
> months from now transitioning from el7.6 to el7.7, or for someone who 
> for whatever reason has stayed on el7.4 (or whatever point release). The 
> plugin should just work in all scenarios as long as all kernels are 
> available to yum (in reality it doesn't even need to be all kernels, 
> just the base kernel from each point release).
> 

It seems we have a simple solution here. On CentOS systems, users can 
replicate RHEL behaviour by enabling the C7 vault repos which contain 
all previous packages, either permanently in the CentOS-Vault.repo 
config file, or on the command line with:

--enablerepo=C7\*

Given that, I will deprecate and remove my rather crude workaround in 
the yum plugin, update the package and release it for those who wish to 
use it.