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+---
+title: Jupyterhub on Merlin7
+#tags: 
+keywords: jupyterhub, jupyter, jupyterlab, notebook, notebooks
+last_updated: 24 July 2025
+summary: "Jupyterhub service description"
+sidebar: merlin7_sidebar
+permalink: /merlin7/jupyterhub.html
+---
+
+Jupyterhub provides [jupyter notebooks](https://jupyter.org/) that are launched on
+cluster nodes of merlin and can be accessed through a web portal.
+
+## Accessing Jupyterhub and launching a session
+
+The service is available inside of PSI (or through a VPN connection) at
+
+**<https://merlin7-jupyter01.psi.ch:8000/hub/>**
+
+
+   1. **Login**: You will be presented with a **Login** web page for
+      authenticating with your PSI account.
+   1. **Spawn job**: The **Spawner Options** page allows you to
+      specify the properties (Slurm partition, running time,...) of
+      the batch jobs that will be running your jupyter notebook. Once
+      you click on the `Spawn` button, your job will be sent to the
+      Slurm batch system. If the cluster is not currently overloaded
+      and the resources you requested are available, your job will
+      usually start within 30 seconds.
+
+### Recommended partitions
+
+Running on the `merlin7` cluster and using the `interactive` partition would
+in general guarantee fast access to resources. Keep in mind, that this partition
+has a limit of 12 hours.
+
+## Requesting additional resources
+
+The **Spawner Options** page covers the most common options. These are used to
+create a submission script for the jupyterhub job and submit it to the slurm
+queue. Additional customization can be implemented using the *'Optional user
+defined line to be added to the batch launcher script'* option. This line is
+added to the submission script at the end of other `#SBATCH` lines. Parameters can
+be passed to SLURM by starting the line with `#SBATCH`, like in [Running Slurm
+Scripts](/merlin7/running-jobs.html). Some ideas:
+
+**Request additional memory**
+
+```
+#SBATCH --mem=100G
+```
+
+**Request multiple GPUs** (gpu partition only)
+
+```
+#SBATCH --gpus=2
+```
+
+**Log additional information**
+
+```
+hostname; date; echo $USER
+```
+
+Output is found in `~/jupyterhub_batchspawner_<jobid>.log`.
+
+## Contact
+In case of problems or requests, please either submit a **[PSI Service
+Now](https://psi.service-now.com/psisp)** incident containing *"Merlin
+Jupyterhub"* as part of the subject, or contact us by mail through
+<merlin-admins@lists.psi.ch>.