Unable to add more than one host to mesos environment

I have four vms. vm4, vm5, vm6, vm7. I start rancher on vm4 and go to rancher UI, then create a Mesos environment. change the host registration URL to, then use add host to get command and run command on vm5. I can see a host vm5 is up in infrustructure screen and I am able go to Mesos UI which point to vm5. Now if I add host in vm6, now infrustrure screen show only vm6 host. it seems vm5 is replaced by vm6.
why? I thought it will show two host this time.

This sounds like they are created from the same snapshot/image/AMI/etc and all have the same uuid on disk, so when they call in to register they are all the “same” host.

rm -rf /var/lib/rancher/state and docker volume rm rancher-agent-state before imaging (or don’t have run the agent at all before imaging)

So rancher save some meta data in /var/lib/rancher/state file? I think the problem is I clone vm5/6/7 from vm4, so inherited same snapshot/image/ etc.

The two command are the way to clean up rancher related meta data if you want to do everything from scratch?