I work on Lustre development. Lustre uses a lot of kernel symbols not covered by the kABI stability guarantee and we already need to maintain configure checks for all of the other kernels (SuSe, Ubuntu, mainline, etc) that don't offer kABI anyway. So in my opinion, it's not worth the effort to adhere to kABI just for RHEL. Especially when RHEL derivatives might not offer the same guarantees. DKMS works well enough, especially for something open source like Lustre.
Honestly, I'm not sure who kABI is even designed for. All of the drivers I've interacted with the HPC space (NVIDIA, Lustre, vendor network drivers, etc.) don't seem to adhere to kABI. DKMS is far more standard. I'd be interested to know which vendors are making heavy use of it.
Honestly, I'm not sure who kABI is even designed for. All of the drivers I've interacted with the HPC space (NVIDIA, Lustre, vendor network drivers, etc.) don't seem to adhere to kABI. DKMS is far more standard. I'd be interested to know which vendors are making heavy use of it.