Systems using software raids cannot realiably upgrade to the next major version of RHEL (e.g. RHEL 7 -> 8). The problem is that such systems expects mdadm module inside the initramfs, but the upgrade initramfs doesn't include the mdadm dracut module, nor the configuration file is present when the initramfs is created.

It's possible that another problems could be discovered, but this seems as the minimum change that needs to be done.

Updated summary

• Fixed following issues: 
  • https://bugzilla.redhat.com/show_bug.cgi?id=2140011
  • https://bugzilla.redhat.com/show_bug.cgi?id=2219544
• For IPU 7 -> 8, systems using dmraid package cannot upgrade successfuly as dmraid is not present on RHEL 8: The DMRAID package has been removed
• Known issues that should be fixed:
  • RHEL-58913