Currently, we cannot filter the VM metrics retrieved by ceilometer-compute by the host where the VM is running, but that would be a very nice addition, specially with Watcher needs in mind.

So, the ceilometer libvirt poller should be also retrieving the hostname of the node where it is running and include it as a label. Maybe this is the file where the modification would go: https://opendev.org/openstack/ceilometer/src/branch/master/ceilometer/compute/virt/libvirt/inspector.py