'Creates and starts containers via the scheduler'

def _start_containers(self, to_add):

    if (not to_add):
        return
    create_threads = [Thread(target=c.create) for c in to_add]
    start_threads = [Thread(target=c.start) for c in to_add]
    [t.start() for t in create_threads]
    [t.join() for t in create_threads]
    if any(((c.state != u'created') for c in to_add)):
        err = u'aborting,    failed    to    create    some    containers'
        log_event(self, err, logging.ERROR)
        self._destroy_containers(to_add)
        raise RuntimeError(err)
    [t.start() for t in start_threads]
    [t.join() for t in start_threads]
    if (set([c.state for c in to_add]) != set([u'up'])):
        err = u'warning,    some    containers    failed    to    start'
        log_event(self, err, logging.WARNING)
    try:
        config = self.config_set.latest()
        if (u'HEALTHCHECK_URL' in config.values.keys()):
            self._healthcheck(to_add, config.values)
    except Config.DoesNotExist:
        pass
