ELRepo and CentOS Stream

As many of you are aware, Red Hat have chosen to discontinue CentOS Linux 8 at the end of 2021 and have proposed CentOS Stream as its replacement in many environments [1]. We are still in the phase of trying to figure out what these changes mean for us and how they will impact ELRepo users. 

 ELRepo has always taken the stance that we support RHEL, and by extention that includes all RHEL compatible rebuilds such as CentOS and Scientific Linux. The kmod standard that ELRepo uses to package and deliver drivers for RHEL is totally dependent on the stable kernel ABI (kABI) that RHEL affords [2]. Unfortunately for us, CentOS Stream, now being upstream of conventional RHEL releases, gets changes to the kernel which are scheduled for the next RHEL minor point release (their kernels diverge). These changes often break kABI compatibility and may cause ELRepo packages to no longer work. 

So what does this mean for ELRepo users in practice? Well, preliminary testing of the first kernel update to EL8.3 in CentOS Stream indicates that 13 out of 44 kmod packages tested were broken by the kernel update. It is simply not possible (for ELRepo) to deliver kmod packages against a constantly moving target such as the CentOS Stream kernel, and even if we could, these newly fixed packages would likely no longer be compatible with RHEL. We would be looking at a whole new repository or project for ELRepo-Stream and we do not have the resources to do that. 

Therefore, for now, ELRepo are unable to officially support CentOS Stream kernels. In reality your package may continue to work but if/when it breaks, we will not be able to officially support it. Hopefully CentOS will be able to offer a solution that allows ELRepo packages to continue to work on CentOS Stream. 

ELRepo also offers kernel-ml and kernel-lt packages for EL8 and these can be used on CentOS-Stream to provide a modern kernel (mainline or longterm) with native support for the legacy hardware Red Hat removed. These newer kernels may provide a convenient solution for some users whose hardware is not natively supported on CentOS Stream. 

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

[2] https://elrepo.org/wiki/doku.php?id=faq#what_is_a_kabi-tracking_kmod