Currently, there isn't a way to set the storage class to use for the artifact logs used during certification. This results in the 'default' storage class always being used when running 'cao certify'.
Setting 'storage-class' as documented is misleading as this only affects the volumes created during test but not the volume used to store test results. This affects all users trying to use a specific type of storage class for both artifacts and testing.
Workaround is to delete the default storage class and re-create it with same specification as the storage class that is passed in with the '-storage-class ' argument.