Comment 3 for bug 1948427

when juju deploys a MAAS machine sets the "owner-data", some of the keys stored there are juju-controller-uuid, juju-machine-id, juju-model-uuid and juju-units-deployed, this is something that could/should be checked before releasing a maas node.

Let's say host baremetal01 was originally deployed as machine-1 with ubuntu/0 allocated, then baremetal01 gets redeployed as machine-2 with new-ubuntu/0, when "juju remove-unit ubuntu/0" is removed, and juju attempts to remove baremetal01 (since no more units are allocated to machine-1), it should check with maas owner data of baremetal01 that juju-machine-id=="machine-1"