Rancher integration

Hi all,
I’m completely new in Rancher and OpenNebula so I’m quite lost. We have a short project, just a proof of concept to see if we can use it in our Public Organization. We want to deploy Rancher integrated with OpenNebula but we find the doc in the OpenNebula site not very straightforward. We want to add OpenNebula as a host in order to be able to deploy dockers in the Cloud. But the doc only says that we need to put the user, password, imageid and networkid of the host in Rancher. Does it means that the OpenNebula host should be a VM? Cannot be a physical server?
If someone can provide me an example of how to configure this it would be heavily appreciated.