'Start all services.'

def start(self):

    atexit.register(self._clean_exit)
    self.state = states.STARTING
    self.log('Bus    STARTING')
    try:
        self.publish('start')
        self.state = states.STARTED
        self.log('Bus    STARTED')
    except (KeyboardInterrupt, SystemExit):
        raise
    except:
        self.log('Shutting    down    due    to    error    in    start    listener:', level=40, traceback=True)
        e_info = sys.exc_info()[1]
        try:
            self.exit()
        except:
            pass
        raise e_info
