Comment 5 for bug 1970257

I just spent some time on this and was able to reproduce.

The environment:

1) UEFI enabled KVM based VM, commissioned on MAAS 3.1

2) Used a custom storage commissioning script (attached). This produces a disk layout as the following:

GPT Partitioned
/dev/vda1 /boot/efi vfat (500M)
/dev/vda2 /boot ext4 (2G)
/dev/vda3 / ext4 (20G)

3) Used packer-maas to generate a custom RHEL 8.5 image (ISO was downloaded today)

4) Commissioned the machine using custom storage layout and performed a deployment

5) Final grub.cfg was generated with the following lines:

linux ($root)/boot/vmlinuz...
initrd ($root)/boot/initramfs...

entries, that caused the boot to fail. Changing the grub.cfg lines to the following fixes the issue (Remove /boot/):

linux ($root)/vmlinuz...
initrd ($root)/initramfs...

6) Released the machine and deployed using default MAAS 3.1 CentOS 7 image, everything worked out fine.

7) Released the machine and deployed using default MAAS 3.1 CentOS 8 image, experienced the exact same issue.

This seems to be affecting RHEL/CentOS 8 family.

Please let me know if you'd like me to add more testing scenarios and will report back the results.