Server can't start for some users, ImportError: The Jupyter Server requires tornado >=6.1.0

Only one user can’t start notebook server, the pod keep crashloopbackoff, and finally get timeout in jhublab. Works fine for other users, so it’s not the issue with images.

Error message from log:

Traceback (most recent call last):
File “/opt/conda/lib/python3.8/site-packages/jupyter_server/serverapp.py”, line 50, in
assert tornado.version_info >= MIN_TORNADO
AssertionError

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File “/opt/conda/bin/jupyter-labhub”, line 6, in
from jupyterlab.labhubapp import main
File “/opt/conda/lib/python3.8/site-packages/jupyterlab/init.py”, line 7, in
from .labapp import LabApp
File “/opt/conda/lib/python3.8/site-packages/jupyterlab/labapp.py”, line 15, in
from jupyterlab_server import slugify, WORKSPACE_EXTENSION
File “/opt/conda/lib/python3.8/site-packages/jupyterlab_server/init.py”, line 4, in
from .app import LabServerApp
File “/opt/conda/lib/python3.8/site-packages/jupyterlab_server/app.py”, line 7, in
from jupyter_server.extension.application import ExtensionApp, ExtensionAppJinjaMixin
File “/opt/conda/lib/python3.8/site-packages/jupyter_server/extension/application.py”, line 20, in
from jupyter_server.serverapp import ServerApp
File “/opt/conda/lib/python3.8/site-packages/jupyter_server/serverapp.py”, line 52, in
raise ImportError(_i18n(“The Jupyter Server requires tornado >=%s.%s.%s”) % MIN_TORNADO) from e
ImportError: The Jupyter Server requires tornado >=6.1.0

Pod keep crashloopbackoff and get timeout error in jhublab

How to reproduce:

  1. Log in to jhub
  2. Select one profile
  3. Start new server

Version(s):
appVersion: 1.3.0 helmVersion: 0.11.1

I deleted tornado packages in user home dir and issue resolved.