[base-notebook] Cannot connect to server after upgrading to Jupyter Lab 3.0.0

[mirekphd]

After upgrading (by unpinning 3 Jupyter packages in my fork of docker-stacks) Jupyter Lab / Server no longer works (only Notebook is still OK).

To reproduce:

1. Clone my fork mirekphd/docker-stacks (or reproduce it by making this change).
2. build mirekphd/base-notebook container (cd base-notebook and docker build --tag mirekphd/base-notebook .)
3. Try to run Jupyter Lab:
   docker run -d --rm --name base-notebook -p 8989:8888 -e JUPYTER_ENABLE_LAB=1 mirekphd/base-notebook:latest && docker logs -f base-notebook
4. Navigate to localhost:8989 and see the "Unable to connect" browser error.
5. Switch to Notebook (e.g. -e JUPYTER_ENABLE_LAB_NOT) to see it works correctly.

Note that earlier today I raised a less reproducible (closed-source) version of this issue in jupyterlab/jupyterlab#9520, so you may find some additional hints / details there.

[romainx]

Hello,

The problem seems to come from the file jupyter_notebook_config.py that needs to be renamed in jupyter_server_config.py in /etc/jupyter/, and change in this file NotebookApp by ServerApp, see this discussion.

c = get_config()  # noqa: F821
-c.NotebookApp.ip = '0.0.0.0'
-c.NotebookApp.port = 8888
-c.NotebookApp.open_browser = False
+c.ServerApp.ip = '0.0.0.0'
+c.ServerApp.port = 8888
+c.ServerApp.open_browser = False

After these changes the problem is fixed and JupyterLab is accessible.
We have not migrated yet to the 3.0 version, so I will make this change along with the bump of version.

Best

[romainx]

Hello,

Here is the documentation Migrating from Notebook Server explaining this change.

[mirekphd]

Thank you so much @romainx !

The docs even warn about the impending doom: "NBClassic will only work for a limited time. Jupyter Server is likely to evolve beyond a point where Jupyter Notebook frontend will no longer work with the underlying server." How unfortunate that the two interfaces cannot continue to co-exist peacefully...

[FuriouslyCurious]

Hello,

The problem seems to come from the file jupyter_notebook_config.py that needs to be renamed in jupyter_server_config.py in /etc/jupyter/, and change in this file NotebookApp by ServerApp, see this discussion.

c = get_config()  # noqa: F821
-c.NotebookApp.ip = '0.0.0.0'
-c.NotebookApp.port = 8888
-c.NotebookApp.open_browser = False
+c.ServerApp.ip = '0.0.0.0'
+c.ServerApp.port = 8888
+c.ServerApp.open_browser = False

After these changes the problem is fixed and JupyterLab is accessible.
We have not migrated yet to the 3.0 version, so I will make this change along with the bump of version.

Best

Thanks for this solution! If someone running as a non-root user, then these config files should be placed in ~/.jupter config directory.

[phish108]

Hi @FuriouslyCurious @romainx

I tried to apply this hotfix ontop of jupyter/base-notebook:latest by adding

RUN  sed -ire "s/^c.NotebookApp/c.ServerApp/g" /etc/jupyter/jupyter_notebook_config.py

before switching to the container user.

The error persists with the present base-notebook container using JL 3.0.0.

I manually added the fix to .jupyter/jupyter_notebook_config.py without effect.

Despite setting c.ServerApp.open_browser = False I continue to get the following warning

[W ... ServerApp] No web browser found: could not locate runnable browser.

My package list is:

$ conda list | grep jup
jupyter-archive           0.7.0                      py_0    conda-forge
jupyter_client            6.1.7                      py_0    conda-forge
jupyter_core              4.7.0            py38h578d9bd_0    conda-forge
jupyter_server            1.1.3            py38h578d9bd_0    conda-forge
jupyter_telemetry         0.1.0              pyhd8ed1ab_1    conda-forge
jupyterhub                1.2.2            py38h578d9bd_0    conda-forge
jupyterhub-base           1.2.2            py38h578d9bd_0    conda-forge
jupyterlab                3.0.0              pyhd8ed1ab_0    conda-forge
jupyterlab-git            0.22.0                     py_0    conda-forge
jupyterlab_pygments       0.1.2              pyh9f0ad1d_0    conda-forge
jupyterlab_server         2.0.0              pyhd8ed1ab_0    conda-forge

[romainx]

@phish108 you need to first copy the file to jupyter_server_config.py and you have to maintain both files if you want to use either classic notebook and JupyterLab.

RUN sed -re "s/c.NotebookApp/c.ServerApp/g" \
    /etc/jupyter/jupyter_notebook_config.py > /etc/jupyter/jupyter_server_config.py

[phish108]

Couldn't this be part of base-notebook? I understand that both configs do not conflict with each other or am I missing something?

[romainx]

@phish108 Maybe but I have not tested the behavior with the current version of JupyterLab 2.2.9.
I've drafted a PR #1206 that bumps the version of JupyterLab to 3.0.0 but it's not ready right now since it conflicts with some extensions installed in scipy-notebook.
Maybe we could release a kind of intermediate version with this code.