mongodb做为数据库不稳定，请问怎么怎么分析原因？

{

  "taskdb": "mongodb+taskdb://localhost/taskdb",

  "projectdb": "mongodb+projectdb://localhost/projectdb",

  "resultdb": "mongodb+resultdb://localhost/resultdb",

  "webui": {

    "username": "admin",

    "password": "123456",

    "need-auth": true

  }

}

[E 160522 09:37:38 scheduler:499] localhost:27017: [Errno -2] Name or service not known

    Traceback (most recent call last):

      File "/usr/local/lib/python2.7/dist-packages/pyspider/scheduler/scheduler.py", line 494, in run

        self.run_once()

      File "/usr/local/lib/python2.7/dist-packages/pyspider/scheduler/scheduler.py", line 1061, in run_once

        super(ThreadBaseScheduler, self).run_once()

      File "/usr/local/lib/python2.7/dist-packages/pyspider/scheduler/scheduler.py", line 478, in run_once

        self._update_projects()

      File "/usr/local/lib/python2.7/dist-packages/pyspider/scheduler/scheduler.py", line 93, in _update_projects

        for project in self.projectdb.check_update(self._last_update_project):

      File "/usr/local/lib/python2.7/dist-packages/pyspider/database/mongodb/projectdb.py", line 62, in check_update

        for project in self.get_all(fields=('updatetime', 'name')):

      File "/usr/local/lib/python2.7/dist-packages/pyspider/database/mongodb/projectdb.py", line 50, in get_all

        for each in self.collection.find({}, fields):

      File "/usr/local/lib/python2.7/dist-packages/pymongo/cursor.py", line 1090, in next

        if len(self.__data) or self._refresh():

      File "/usr/local/lib/python2.7/dist-packages/pymongo/cursor.py", line 1012, in _refresh

        self.__read_concern))

      File "/usr/local/lib/python2.7/dist-packages/pymongo/cursor.py", line 850, in __send_message

        **kwargs)

      File "/usr/local/lib/python2.7/dist-packages/pymongo/mongo_client.py", line 798, in _send_message_with_response

        exhaust)

      File "/usr/local/lib/python2.7/dist-packages/pymongo/mongo_client.py", line 809, in _reset_on_error

        return func(*args, **kwargs)

      File "/usr/local/lib/python2.7/dist-packages/pymongo/server.py", line 88, in send_message_with_response

        with self.get_socket(all_credentials, exhaust) as sock_info:

      File "/usr/lib/python2.7/contextlib.py", line 17, in __enter__

        return self.gen.next()

      File "/usr/local/lib/python2.7/dist-packages/pymongo/server.py", line 152, in get_socket

        with self.pool.get_socket(all_credentials, checkout) as sock_info:

      File "/usr/lib/python2.7/contextlib.py", line 17, in __enter__

        return self.gen.next()

      File "/usr/local/lib/python2.7/dist-packages/pymongo/pool.py", line 539, in get_socket

        sock_info = self._get_socket_no_auth()

      File "/usr/local/lib/python2.7/dist-packages/pymongo/pool.py", line 573, in _get_socket_no_auth

        sock_info, from_pool = self.connect(), False

      File "/usr/local/lib/python2.7/dist-packages/pymongo/pool.py", line 512, in connect

        _raise_connection_failure(self.address, error)

      File "/usr/local/lib/python2.7/dist-packages/pymongo/pool.py", line 65, in _raise_connection_failure

        raise AutoReconnect(msg)

    AutoReconnect: localhost:27017: [Errno -2] Name or service not known

[I 160522 09:37:38 scheduler:505] scheduler exiting...