Comment 6 for bug 1979280

I am using MAAS 3.3.5 and encountering this as well. As others mentioned, RHEL-9 deployments are failing:

finish: cmd-install/stage-curthooks/builtin/cmd-curthooks: FAIL: curtin command curthooks
Traceback (most recent call last):
  File "/curtin/curtin/commands/main.py", line 202, in main
    ret = args.func(args)
  File "/curtin/curtin/commands/curthooks.py", line 1886, in curthooks
    builtin_curthooks(cfg, target, state)
  File "/curtin/curtin/commands/curthooks.py", line 1851, in builtin_curthooks
    setup_grub(cfg, target, osfamily=osfamily,
  File "/curtin/curtin/commands/curthooks.py", line 804, in setup_grub
    install_grub(instdevs, target, uefi=uefi_bootable, grubcfg=grubcfg)
  File "/curtin/curtin/commands/install_grub.py", line 381, in install_grub
    grub_name, grub_target = get_grub_package_name(target_arch, uefi, rhel_ver)
  File "/curtin/curtin/commands/install_grub.py", line 80, in get_grub_package_name
    raise ValueError('Unsupported RHEL version: %s', rhel_ver)
ValueError: ('Unsupported RHEL version: %s', '9')
('Unsupported RHEL version: %s', '9')
curtin: Installation failed with exception: Unexpected error while running command.
Command: ['curtin', 'curthooks']
Exit code: 3

Thanks,
Alan