'Tag the instance as belonging to this host.  This should be done
while the COMPUTE_RESOURCES_SEMAPHORE is held so the resource claim
will not be lost if the audit process starts.'

def _set_instance_host_and_node(self, instance, nodename):

    instance.host = self.host
    instance.launched_on = self.host
    instance.node = nodename
    instance.save()
