In the following Link, http://docs.openstack.org/user-guide/...

I was able to figure out that we can set these formats for Config-Drive

config_drive_format=iso9660
config_drive_format=vfat

Is there any cloud-init logs which can tell What is the format that has been picked up? if not Logs, is there a way to identify if the config-drive format is vfat or iso9660