hum, this tools is not expected to be used to make a snapshot from your main system. The working directory is already on the / of the host. If your / is set as mountpoint, you risk to go in loop.
This tools was made to make ISO from a fresh installation (installed with e.g. obarun-install) on some another disk/partition and ,thereby, provide an bootable ISO which can be burn on e.g USB stick.
For example, you can create a file, mount it on dev/loop, install what you want with obarun-install then use obarun-mkiso to produce the ISO. Then burn it on USB stick with persitent partition on it :). With this way, you can produce your own rescue disk system with your all prefered tools on it.
Snapshot from the host need to be made with another way.
This tools was made to make ISO from a fresh installation (installed with e.g. obarun-install) on some another disk/partition and ,thereby, provide an bootable ISO which can be burn on e.g USB stick.
For example, you can create a file, mount it on dev/loop, install what you want with obarun-install then use obarun-mkiso to produce the ISO. Then burn it on USB stick with persitent partition on it :). With this way, you can produce your own rescue disk system with your all prefered tools on it.
Snapshot from the host need to be made with another way.