Message-Id: 202204251709
Time: April 26th, 9 am
Affected: All Jupyter-Users
Impact: Service temporarily unavailable

Today between 01.45pm and ca. 4.30pm the service Jupyter-Cloud suffered an outage
resulting in newly logged-in users being unable to spawn their notebook, resulting in a
timeout error.
Notebooks already running at that time were not affected.
During 3-3.30pm as part of the error investigation Jupyterhub, the web user interface of
the service, was shut down resulting in all users being unable to interact with the
service. Running notebooks were not affected.
The cause was a network resource limitation within the service that was exceeded by the
increasing utilization of the service (exceeding 100 concurrent users). In a brief
maintenance tomorrow morning around 09 am a configuration change will greatly extend this
limitation. During the procedure all notebooks and the user interface will be stopped and
the service unavailable for a few minutes.
Due to the high demand on the service the maintenance is performed at the earliest
possibility and interruption is kept to a minimum.