def build_filter_properties(scheduler_hints, forced_host, forced_node,
    instance_type):
    """Build the filter_properties dict from data in the boot request."""
    filter_properties = dict(scheduler_hints=scheduler_hints)
    filter_properties['instance_type'] = instance_type
    if forced_host:
        filter_properties['force_hosts'] = [forced_host]
    if forced_node:
        filter_properties['force_nodes'] = [forced_node]
    return filter_properties
