'Spawn or kill metadata proxy.
According to return from driver class, spawn or kill the metadata
proxy process. Spawn an existing metadata proxy or kill a nonexistent
metadata proxy will just silently return.'

def update_isolated_metadata_proxy(self, network):

    should_enable_metadata = self.dhcp_driver_cls.should_enable_metadata(self.conf, network)
    if should_enable_metadata:
        self.enable_isolated_metadata_proxy(network)
    else:
        self.disable_isolated_metadata_proxy(network)
