Jupyter Notebook

JupyterLab is a flexible, popular literate-computing web application for creating notebooks containing code, equations, visualization, and text. Notebooks are documents that contain both computer code and rich text elements (paragraphs, equations, figures, widgets, links). They are human-readable documents containing analysis descriptions and results but are also executable data analytics artifacts. Notebooks are associated with kernels, processes that actually execute code. Notebooks can be shared or converted into static HTML documents. They are a powerful tool for reproducible research and teaching.

Install Jupyter

While JupyterLab runs code in Jupyter notebooks for many programming languages, Python is a requirement (Python 3.3 or greater, or Python 2.7) for installing the JupyterLab. New users may wish to install JupyterLab in a Conda environment. Hereafter, the pip package manager will be used to install JupyterLab.

We strongly recommend to use the Python module provided by the ULHPC and installing jupyter inside a Python virtual environment after upgrading pip.

$ si
$ module load lang/Python #Loading default Python
$ python -m venv ~/environments/jupyter_env
$ source ~/environments/jupyter_env/bin/activate
$ python -m pip install --upgrade pip
$ python -m pip install jupyterlab

Warning

Modules are not allowed on the access servers. To test interactively Singularity, remember to ask for an interactive job first using for instance the si tool.

Once JupyterLab is installed along with , you can start to configure your installation setting the environment variables corresponding to your needs:

• JUPYTER_CONFIG_DIR: Set this environment variable to use a particular directory, other than the default, for Jupyter config files
• JUPYTER_PATH: Set this environment variable to provide extra directories for the data search path. JUPYTER_PATH should contain a series of directories, separated by os.pathsep(; on Windows, : on Unix). Directories given in JUPYTER_PATH are searched before other locations. This is used in addition to other entries, rather than replacing any
• JUPYTER_DATA_DIR: Set this environment variable to use a particular directory, other than the default, as the user data directory
• JUPYTER_RUNTIME_DIR: Set this to override where Jupyter stores runtime files
• IPYTHONDIR: If set, this environment variable should be the path to a directory, which IPython will use for user data. IPython will create it if it does not exist.

JupyterLab is now installed and ready.

Installing the classic Notebook

JupyterLab (jupyterlab) is a new package which automates many task that where performed manually in the traditional Jupyter package (jupyter). If you prefer to install the classic notebook, you also need to install the IPython manually as well, replacing

python -m pip install jupyterlab

with:

python -m pip install jupyter ipykernel

Providing access to kernels of other environments

JupyterLab makes sure that a default IPython kernel is available, with the environment (and the Python version) with which the lab was created. Other environments can export a kernel to a JupyterLab instance, allowing the instance to launch interactive session inside environments others from the environment where JupyterLab is installed.

You can setup kernels with different environments on the same notebook. Create the environment with the Python version and the packages you require, and then register the kernel in any environment with Jupyter (lab or classic notebook) installed. For instance, if we have installed Jupyter in ~/environments/jupyter_env:

source ~/environments/other_python_venv/bin/activate
python -m pip install ipykernel
python -m ipykernel install --prefix=${HOME}/environments/jupyter_env --name other_python_env --display-name "Other Python env"
deactivate

Then all kernels and their associated environment can be started from the same Jupyter instance in the ~/environments/jupyter_env Python venv.

You can also use the flag --user instead of --prefix to install the kernel in the default system location available to all Jupyter environments for a user.

Kernels for Conda environments

If you would like to install a kernel in a Conda environment, install the ipykernel from the conda-forge channel. For instance,

micromamba install --name conda_env conda-forge::ipykernel
micromamba run --name conda_env python -m ipykernel install --prefix=${HOME}/environments/jupyter_env --name other_python_env --display-name "Other Python env"

will make your conda environment, conda_env, available in the kernel launched from the ~/environments/jupyter_env Python venv.

Starting a Jupyter Notebook

Jupyter notebooks must be started as slurm jobs. The following script is a template for Jupyter submission scripts that will rarely need modifications. Most often you will need to modify the session duration (--time SBATCH option).

Slurm Launcher script for Jupyter Notebook

#!/usr/bin/bash --login
#SBATCH --job-name=Jupyter
#SBATCH --nodes=1
#SBATCH --ntasks-per-node=1
#SBATCH --cpus-per-task=2   # Change accordingly, note that ~1.7GB RAM is proivisioned per core
#SBATCH --partition=batch
#SBATCH --qos=normal
#SBATCH --output=%x_%j.out  # Print messages to 'Jupyter_<job id>.out
#SBATCH --error=%x_%j.err   # Print debug messages to 'Jupyter_<job id>.err
#SBATCH --time=0-01:00:00   # Change maximum allowable jupyter server uptime here

print_error_and_exit() { echo "***ERROR*** $*"; exit 1; }
module purge || print_error_and_exit "No 'module' command"

# Load the default Python 3 module
module load lang/Python
source "${HOME}/environments/jupyter_env/bin/activate"

declare loopback_device="127.0.0.1"
declare port="8888"
declare connection_instructions="connection_instructions.log"

jupyter lab --ip=${loopback_device} --port=${port} --no-browser &
declare lab_pid=$!

# Add connection instruction
echo "# Connection instructions" > "${connection_instructions}"
echo "" >> "${connection_instructions}"
echo "To access the jupyter notebook execute on your personal machine:" >> "${connection_instructions}"
echo "ssh -J ${USER}@access-${ULHPC_CLUSTER}.uni.lu:8022 -L ${port}:${loopback_device}:${port} ${USER}@$(hostname -i)" >> "${connection_instructions}"
echo "" >> "${connection_instructions}"
echo "To access the jupyter notebook if you have setup a special key (e.g ulhpc_id_ed25519) to connect to cluster nodes execute on your personal machine:" >> "${connection_instructions}"
echo "ssh -i ~/.ssh/hpc_id_ed25519 -J ${USER}@access-${ULHPC_CLUSTER}.uni.lu:8022 -L ${port}:${loopback_device}:${port} ${USER}@$(hostname -i)" >> "${connection_instructions}"
echo "" >> "${connection_instructions}"
echo "Then navigate to:" >> "${connection_instructions}"

# Wait for the server to start
sleep 2s
# Wait and check that the landing page is available
curl \
    --connect-timeout 10 \
    --retry 5 \
    --retry-delay 1 \
    --retry-connrefused \
    --silent --show-error --fail \
    "http://${loopback_device}:${port}" > /dev/null
# Note down the URL
jupyter lab list 2>&1 \
    | grep -E '\?token=' \
    | awk 'BEGIN {FS="::"} {gsub("[ \t]*","",$1); print $1}' \
    | sed -r 's/([0-9]{1,3}\.){3}[0-9]{1,3}/127\.0\.0\.1/g' \
    >> "${connection_instructions}"

# Save some debug information
echo -e '\n===\n'

echo "AVAILABLE LABS"
echo ""
jupyter lab list

echo -e '\n===\n'

echo "CONFIGURATION PATHS"
echo ""
jupyter --paths

echo -e '\n===\n'

echo "KERNEL SPECIFICATIONS"
echo ""
jupyter kernelspec list

# Wait for the user to terminate the lab
wait ${lab_pid}

Once your job is running (see Joining/monitoring running jobs), you can combine

• ssh forwarding, and
• an ssh jump through the login node,

to connect to the notebook from your laptop. Open a terminal on your laptop and copy-paste the ssh command contained in the file connection_instructions.log, and then navigate to the webpage link provided.

Example content of connection_instructions.log

> cat connection_instructions.log
# Connection instructions

To access the jupyter notebook execute on your personal machine:
ssh -J gkafanas@access-aion.uni.lu:8022 -L 8888:127.0.0.1:8888 gkafanas@172.21.12.29

To access the jupyter notebook if you have setup a special key (e.g ulhpc_id_ed25519) to connect to cluster nodes execute on your personal machine:
ssh -i ~/.ssh/ulhpc_id_ed25519 -J gkafanas@access-aion.uni.lu:8022 -L 8888:127.0.0.1:8888 gkafanas@172.21.12.29

Then navigate to:
http://127.0.0.1:8888/?token=b7cf9d71d5c89627250e9a73d4f28cb649cd3d9ff662e7e2

As the instructions suggest, you access the jupyter lab server in the compute node by calling

ssh -J gkafanas@access-aion.uni.lu:8022 -L 8888:127.0.0.1:8888 gkafanas@172.21.12.29

an SSH command that

• opens a connection to your allocated cluster node jumping through the login node (-J gkafanas@access-aion.uni.lu:8022 gkafanas@172.21.12.29), and
• exports the port to the jupyter server in the local machine (-L 8888:127.0.0.1:8888).

Then, open the connection to the browser in your local machine by following the given link:

http://127.0.0.1:8888/?token=b7cf9d71d5c89627250e9a73d4f28cb649cd3d9ff662e7e2

The link provides the access token, so you should be able to login without a password.

Warning

Do not forget to click on the quit button when finished to stop the Jupyter server and release the resources. Note that in the last line of the submission script the job waits for your Jupyter service to finish.

If you encounter any issues, have a look in the debug output in Jupyter_<job id>.err. Generic information about the setup of your system is printed in Jupyter_<job id>.out.

Typical content of Jupyter_<job id>.err

> cat Jupyter_3664038.err 
[I 2024-11-13 23:19:52.538 ServerApp] jupyter_lsp | extension was successfully linked.
[I 2024-11-13 23:19:52.543 ServerApp] jupyter_server_terminals | extension was successfully linked.
[I 2024-11-13 23:19:52.547 ServerApp] jupyterlab | extension was successfully linked.
[I 2024-11-13 23:19:52.766 ServerApp] notebook_shim | extension was successfully linked.
[I 2024-11-13 23:19:52.808 ServerApp] notebook_shim | extension was successfully loaded.
[I 2024-11-13 23:19:52.812 ServerApp] jupyter_lsp | extension was successfully loaded.
[I 2024-11-13 23:19:52.813 ServerApp] jupyter_server_terminals | extension was successfully loaded.
[I 2024-11-13 23:19:52.814 LabApp] JupyterLab extension loaded from /home/users/gkafanas/environments/jupyter_env/lib/python3.11/site-packages/jupyterlab
[I 2024-11-13 23:19:52.814 LabApp] JupyterLab application directory is /mnt/aiongpfs/users/gkafanas/environments/jupyter_env/share/jupyter/lab
[I 2024-11-13 23:19:52.815 LabApp] Extension Manager is 'pypi'.
[I 2024-11-13 23:19:52.826 ServerApp] jupyterlab | extension was successfully loaded.
[I 2024-11-13 23:19:52.827 ServerApp] Serving notebooks from local directory: /mnt/aiongpfs/users/gkafanas/support/jupyter
[I 2024-11-13 23:19:52.827 ServerApp] Jupyter Server 2.14.2 is running at:
[I 2024-11-13 23:19:52.827 ServerApp] http://127.0.0.1:8888/lab?token=fe665f90872927f5f84be627f54cf9056908c34b3765e17d
[I 2024-11-13 23:19:52.827 ServerApp]     http://127.0.0.1:8888/lab?token=fe665f90872927f5f84be627f54cf9056908c34b3765e17d
[I 2024-11-13 23:19:52.827 ServerApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
[C 2024-11-13 23:19:52.830 ServerApp] 

    To access the server, open this file in a browser:
        file:///home/users/gkafanas/.local/share/jupyter/runtime/jpserver-2253096-open.html
    Or copy and paste one of these URLs:
        http://127.0.0.1:8888/lab?token=fe665f90872927f5f84be627f54cf9056908c34b3765e17d
        http://127.0.0.1:8888/lab?token=fe665f90872927f5f84be627f54cf9056908c34b3765e17d
[I 2024-11-13 23:19:52.845 ServerApp] Skipped non-installed server(s): bash-language-server, dockerfile-language-server-nodejs, javascript-typescript-langserver, jedi-language-server, julia-language-server, pyright, python-language-server, python-lsp-server, r-languageserver, sql-language-server, texlab, typescript-language-server, unified-language-server, vscode-css-languageserver-bin, vscode-html-languageserver-bin, vscode-json-languageserver-bin, yaml-language-server
[I 2024-11-13 23:19:53.824 ServerApp] 302 GET / (@127.0.0.1) 0.47ms

Typical content of Jupyter_<job id>.err

> cat Jupyter_3664038.out

===

AVAILABLE LABS

Currently running servers:
http://127.0.0.1:8888/?token=fe665f90872927f5f84be627f54cf9056908c34b3765e17d :: /mnt/aiongpfs/users/gkafanas/support/jupyter

===

CONFIGURATION PATHS

config:
    /home/users/gkafanas/environments/jupyter_env/etc/jupyter
    /mnt/aiongpfs/users/gkafanas/.jupyter
    /usr/local/etc/jupyter
    /etc/jupyter
data:
    /home/users/gkafanas/environments/jupyter_env/share/jupyter
    /home/users/gkafanas/.local/share/jupyter
    /usr/local/share/jupyter
    /usr/share/jupyter
runtime:
    /home/users/gkafanas/.local/share/jupyter/runtime

===

KERNEL SPECIFICATIONS

Available kernels:
  other_python_env    /home/users/gkafanas/environments/jupyter_env/share/jupyter/kernels/other_python_env
  python3             /home/users/gkafanas/environments/jupyter_env/share/jupyter/kernels/python3 

Password protected access

You can also set a password when launching the jupyter lab as detailed in the Jupyter official documentation. In that case, simply direct you browser to the URL http://127.0.0.1:8888/ and provide your password. You can see bellow an example of the login page.

Typical content of a password protected login page

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Last update: May 7, 2025