Describe the enhancement

Investigate adding UKI support for Fedora CoreOS for selected cloud / hardware platforms.

UKI are Unified Kernel Images including the kernel, initrd and kernel command line in a single EFI binary that is optionally Secure Boot signed.

System details

Only platforms where it makes sense.

Additional information

See:

• https://fedoraproject.org/wiki/Changes/Unified_Kernel_Support_Phase_1
• https://fedoraproject.org/wiki/Changes/Unified_Kernel_Support_Phase_2
• https://discussion.fedoraproject.org/t/f40-change-proposal-unified-kernel-support-phase-2-system-wide/98298
• Cloud-Base-UEFI-UKI image in Fedora: https://pagure.io/fedora-kiwi-descriptions/blob/rawhide/f/teams/cloud/cloud.xml#_21

Required work / dependencies:

• Fedora CoreOS images should support discoverable partitions #1038
• Support UKI ostreedev/ostree#2753

Not strictly required but would be really nice to have:

• systemd-boot support ostreedev/ostree#1719

Related but not required:

• Support alternate cmdline entries in UKIs systemd/systemd#24539