'Initialize the NamespaceManager.
:param agent_conf: configuration from l3 agent
:param driver: to perform operations on devices
:param metadata_driver: used to cleanup stale metadata proxy processes'

def __init__(self, agent_conf, driver, metadata_driver=None):

    self.agent_conf = agent_conf
    self.driver = driver
    self._clean_stale = True
    self.metadata_driver = metadata_driver
    if metadata_driver:
        self.process_monitor = external_process.ProcessMonitor(config=agent_conf, resource_type='router')
