Crazy disk behaviour

I’m fishing for some ideas here, got a weird behaviour where the disk driver types seem to be not as strict as you’d think they are.

Versions of the related components and OS (frontend, hypervisors, VMs):
KVM, ONE 5.6

Steps to reproduce:

  • import SUSE leap 15.0/15.1 vagrant box (ask me for link if you want to try and can’t find)
  • machine model i440FX
  • set DEV_PREFIX etc. to sd, sda
  • do not enable context
  • boot
  • systemd will hang saying there’s startup jobs running for 2 disk paths (one /dev/sda2, one is a uuid)

vs.

  • set DEV_PREFIX etc. to hd, hda
  • do not enable context
  • boot
  • system will come up.
  • disk will be detected as “sda” will a complete driver attachment as a scsi disk.

Current results:
sda shows up as sda
setting to hda doesn’t get me a sda.

Expected results:
the drivers are the ones that it should be using - and the system boots even though using systemd.

I found this can happen with SUSE 15.1 and CentOS8 - so I suppose it’s a “very recent kernel” thing… i mean “a feature”.
If someone can confirm the behaviour, that would help a lot.