1. 这个本来就有吧
2. readonly file system 也是本来就这样的，runtime error 得点进去看下详情。

有去找log
出現以下錯誤：

Traceback (most recent call last):
File "/code/service.py", line 19, in _request
"Content-Type": "application/json"}, timeout=5).text
File "/usr/local/lib/python3.6/dist-packages/requests/api.py", line 119, in post
return request('post', url, data=data, json=json, **kwargs)
File "/usr/local/lib/python3.6/dist-packages/requests/api.py", line 61, in request
return session.request(method=method, url=url, **kwargs)
File "/usr/local/lib/python3.6/dist-packages/requests/sessions.py", line 530, in request
resp = self.send(prep, **send_kwargs)
File "/usr/local/lib/python3.6/dist-packages/requests/sessions.py", line 643, in send
r = adapter.send(request, **kwargs)
File "/usr/local/lib/python3.6/dist-packages/requests/adapters.py", line 516, in send
raise ConnectionError(e, request=request)
requests.exceptions.ConnectionError: HTTPConnectionPool(host='oj-backend', port=8000): Max retries exceeded with url: /api/judge_server_heartbeat/ (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7f628416ea90>: Failed to establish a new connection: [Errno -2] Name or service not known',))

During handling of the above exception, another exception occurred: