500 Internal Server Error

[Larionov__Daniil]

Hi, i was using devcloud and planning to explore large dataset, but after several kernel restarts jupyter starts freezing at the stage of "Kernel is starting, please wait...". Then i've closed the notebook and created a new one, but it gives 500 error. The same happens even if i restart my server via control panel, or choose different kernel. However, Jupyter Terminal and any other feature works well. I've tried cleaning cookies and logging in via incognito mode, but 500 error still happens.

[Rohith_K_Intel]

Hi,

We are able to access jupyter notebook in DevCloud without any error.

Could you please share the DevCloud account details  so that we can check with the corresponding team whether there's any issue with the account?

[Larionov__Daniil]

Thanks for response

Here is my account details, as provided in email:

User Name: u35804
Node Name: c009

Please let me know if you need any other details.

[Andrey_Vladimirov]

Hi Daniil,

I checked the issue by viewing the Jupyter server log file, which we place in ~/.jupyter/logs/logs.txt. Here is what I found upon trying to start a new notebook:

[E 2019-12-19 09:18:09.333 SingleUserNotebookApp web:1788] Uncaught exception GET /user/u35804/notebooks/Untitled3.ipynb (172.18.0.1)
    HTTPServerRequest(protocol='http', host='jupyter.devcloud.intel.com', method='GET', uri='/user/u35804/notebooks/Untitled3.ipynb', version='HTTP/1.1', remote_ip='172.18.0.1')
    Traceback (most recent call last):
      File "/home/u35804/.local/lib/python3.6/site-packages/tornado/web.py", line 1697, in _execute
        result = method(*self.path_args, **self.path_kwargs)
      File "/home/u35804/.local/lib/python3.6/site-packages/tornado/web.py", line 3174, in wrapper
        return method(self, *args, **kwargs)
      File "/jhub/lib/python3.6/site-packages/notebook/notebook/handlers.py", line 59, in get
        get_custom_frontend_exporters=get_custom_frontend_exporters
      File "/jhub/lib/python3.6/site-packages/notebook/base/handlers.py", line 425, in render_template
        return template.render(**ns)
      File "/home/u35804/.local/lib/python3.6/site-packages/jinja2/asyncsupport.py", line 76, in render
        return original_render(self, *args, **kwargs)
      File "/home/u35804/.local/lib/python3.6/site-packages/jinja2/environment.py", line 1008, in render
        return self.environment.handle_exception(exc_info, True)
      File "/home/u35804/.local/lib/python3.6/site-packages/jinja2/environment.py", line 780, in handle_exception
        reraise(exc_type, exc_value, tb)
      File "/home/u35804/.local/lib/python3.6/site-packages/jinja2/_compat.py", line 37, in reraise
        raise value.with_traceback(tb)
      File "/jhub/lib/python3.6/site-packages/notebook/templates/notebook.html", line 1, in top-level template code
        {% extends "page.html" %}
      File "<template>", line 2, in top-level template code
      File "/jhub/lib/python3.6/site-packages/notebook/templates/page.html", line 154, in top-level template code
        {% block header %}
      File "/jhub/lib/python3.6/site-packages/notebook/templates/notebook.html", line 120, in block "header"
        {% for exporter in get_custom_frontend_exporters() %}
      File "/jhub/lib/python3.6/site-packages/notebook/notebook/handlers.py", line 19, in get_custom_frontend_exporters
        from nbconvert.exporters.base import get_export_names, get_exporter
      File "/jhub/lib/python3.6/site-packages/nbconvert/__init__.py", line 7, in <module>
        from . import postprocessors
      File "/jhub/lib/python3.6/site-packages/nbconvert/postprocessors/__init__.py", line 5, in <module>
        from .serve import ServePostProcessor
      File "/jhub/lib/python3.6/site-packages/nbconvert/postprocessors/serve.py", line 19, in <module>
        class ProxyHandler(web.RequestHandler):
      File "/jhub/lib/python3.6/site-packages/nbconvert/postprocessors/serve.py", line 21, in ProxyHandler
        @web.asynchronous
    AttributeError: module 'tornado.web' has no attribute 'asynchronous'

You can see that the error was triggered by the package "tornado" installed in your home directory. I opened a terminal in your Jupyter server and ran "pip uninstall tornado". After that, notebooks started working for your account.

Andrey