Dask Hub/JupyterHub - Cannot start Python Kernel

JupyterHub
1

I deployed Dask Hub (Dask Gateway + Jupyterhub) on Google Kubernetes Engine using helm. I am experiencing trouble fetching the Python Kernel when I start up my jupyter notebook instance. This error occurs when I am on my company’s VPN, but no error occurs when I’m not on my company’s VPN. I’m going to guess that this is firewall related, but I don’t know enough about the internal of the Jupyterhub kernel to understand why it’s being blocked. Could someone please shed some light on this?

I used the DaskHub helm chart (4.4.1)

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2

Could you try opening your browser’s developer console and look for error messages?

3

We were trying to looking into the error and route it and I got Google Cloud Support involved, but we weren’t able to diagnose the issue

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4

I think your best option is to talk to your VPN and company network administrators. There are lots of reasons requests could be failing, examples that have previously appeared on this forum include websocket requests and large JavaScript responses being blocked by proxies or firewalls.

5

Okay - I’ll talk to my network administrators. One other suggestion recommended by the StackOverflow community [1] is to add this to the configuration file:

jupyterhub:
  hub:
    extraConfig: |
      c.JupyterHub.hub_connect_ip = '0.0.0.0'
      c.JupyterHub.bind_url = 'http://127.0.0.1:8000'
  singleuser:
    extraEnv:
      DASK_GATEWAY__CLUSTER__OPTIONS__IMAGE: '{JUPYTER_IMAGE_SPEC}'

But I get the following error:

coalesce.go:196: warning: cannot overwrite table with non table for extraConfig (map[])

Do you know how I can update the jupyterhub config via helm?

[1] https://stackoverflow.com/questions/64439817/dask-hub-jupyterhub-cannot-start-python-kernel

6

Given that your JupyterHub/Dask installation works outside your VPN it’s unlikely that changing your JupyterHub configuration is necessary.