If you are a developer who comes from data science used to working with containers directly on interactive Jupyter notebooks then this tutorial is for you. We go through a simple procedure for setting up and working with Jupyter notebooks on a supercomputer.

In this tutorial, you will

• Transfer a Docker container and convert it to a Singularity container on the supercomputer.
• Start a Jupyter instance on a compute note on the supercomputer.
• Access the remote Jupyter kernel from a local Jupyter notebook on your machine.

As an example, we will use EuroHPC JU supercomputer LUMI, one of the fastest in the world. The same procedure also works on Leonardo supercomputer.

Prerequisites

1. For this tutorial, you will need access to a supercomputer.
2. You will need a basic understanding of what a container is.
3. You’ll also need some knowledge of the UNIX Shell commands.

Disclaimer
→ The workflow described in this tutorial may be different for other supercomputers. Get help from the supercomputer’s documentation or the admin support team if needed.
→ Using containers with GPU capabilities can be even more supercomputer-specific due to different architectures (NVIDIA, AMD, etc). ENCCS and other EuroCC Competence Centres can give you hands-on support if you are a company located in Europe.

LUMI has an easy-to-use web interface where you can run Jupyter Notebooks among other interfaces. This is NOT a tutorial on how to use that interface. It is a more general approach to how to run Jupyter Notebooks on any supercomputer by using a technique called SSH-tunneling.

1 Docker and Singularity containers

A container is a unit of software that packages up module dependencies so your code or application runs quickly and reliably from one computing environment to another. Docker is a type of container that is very popular among developers. However, Docker cannot run on a supercomputer as it requires root access. Docker containers can however be easily converted into Singularity containers, which can run on HPC systems.

We will not go through how to build a Docker container in this tutorial. There are multiple containers already online on Github or https://hub.docker.com. More specifically for our tutorial, the Jupyter team is maintaining a list of containers that one can easily use. We will use base-notebook which has a basic Jupyter Lab functionality. You can go through the list and pick the container that feels right for your workflow.

2 Building the container image on the supercomputer

Let’s first log into LUMI. Start your terminal app and type

ssh -i PATH_TO_SSH_KEY/id_ed25519 USER_NAME@lumi.csc.fi

Replace PATH_TO_SSH_KEY with the path to your SSH keys (e.g. ~/.ssh/id_rsa) and USER_NAME with the one that LUMI provided you with. If you have access to a different supercomputer the address at the end will be different.

Check our previous tutorial to learn more on how to get started with a supercomputer, including creating SSH keys, logging in, and running jobs.

Once you log in you will see the following

*  ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒  *   *      *
                                                       *      *  *
   * ████       ████   ████   █████▄    ▄█████   ████     *     *
 *   ████       ████   ████   ████ █▄  ▄█ ████   ████         ,    *,
     ████       ████   ████   ████  ████  ████   ████  *   *  |\_ _/|
     ████       ████   ████   ████   ▀▀   ████   ████   *    .| ." ,|
  *  ████       ████   ████   ████        ████   ████        /(  \_\)
     ████       ████   ████   ████        ████   ████       /    ,-,|
 *   ████▄▄▄▄▄  ▀███   ███▀   ████        ████   ████ *    * /      \
     █████████    ▀▀███▀▀     ████        ████   ████  * ,/  (      *
 *                                                     ,/       |  /
  * ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒/    \  * || |
                 *              *               ,_   (       )| || |
*   *    *    The Supercomputer of the North  * | `\_|   __ /_| || |
        **               *            * *       \_____\______)\__)__)
   .********----------*******-------******----------****************.
   |User guide and support _________________________________________|
   |         https://docs.lumi-supercomputer.eu                     |
 * |         https://lumi-supercomputer.eu/user-support             |

USER_NAME@uan03:~>

The first point of contact is through a login node. The login node is used to administer your jobs, like creating folders installing modules, etc. We will later allocate a compute node to start using our notebooks.

Building the Singularity container

The first job we need to do is building our container on LUMI. This may take several GB of our allocated storage depending on your container. By running the command pwd we see that we are located in our user folder /users/USER_NAME. Our user folder may not have the capacity to store the container image, so we choose to store it in the allocated project folder. On LUMI we can access this folder by typing

cd /scratch/PROJECT_NAME 

You replace PROJECT_NAME with the project name that LUMI has provided you with (e.g. project_355000440).

Now we have to create a folder where the container image will be residing. We call it jupyter-tunnel and we select the folder.

mkdir jupyter-tunnel
cd jupyter-tunnel

Now we can build the container by pulling the jupyter-base docker file from https://hub.docker.com and transform it into a Singularity container simply by running the following command.

singularity pull base.sif docker://jupyter/base-notebook

This command pulls a docker container from https://hub.docker.com/r/jupyter/base-notebook and stores it as a singularity container called base.sif in our folder.

There are multiple containers you can use on https://jupyter-docker-stacks.readthedocs.io/en/latest/using/selecting.html. GPU-ready containers may be supercomputer-specific due to the different architectures (LUMI has AMD GPU, while Leonardo has NVIDIA GPUs). Contact us or the system admin teams of the supercomputer you have access to for more information.

You will have to do the steps above only once. You can repeat the procedure if you need to pull different containers or update the current ones.

3 Starting a Jupyter instance on the supercomputer

First, we need to allocate a compute node as we mentioned earlier. On supercomputers, we do that with SLURM. See more on that in our previous tutorial. For this example, we will use the salloc command that reserves an interactive compute node for us to run our Jupyter Notebook.

Allocating a compute node

To see what nodes and partitions there are on LUMI we type the command

sinfo -s

PARTITION   AVAIL  TIMELIMIT   NODES(A/I/O/T) NODELIST
debug          up      30:00          6/2/0/8 nid[002500-002501,002504-002506,002595-002597]
interactive    up    8:00:00          4/0/0/4 nid[002502,002507,002594,002599]
q_fiqci     inact      15:00          0/1/0/1 nid002598
q_industry     up      15:00          0/1/0/1 nid002598
q_nordiq       up      15:00          0/1/0/1 nid002503
small          up 3-00:00:00    276/17/13/306 nid[002280-002499,002508-002593]
standard       up 2-00:00:00 1442/217/69/1728 nid[001000-002279,002600-003047]
dev-g          up    3:00:00       32/15/1/48 nid[005002-005025,007954-007977]
small-g        up 3-00:00:00      193/2/3/198 nid[005026-005123,007852-007951]
standard-g     up 2-00:00:00 2469/87/172/2728 nid[005124-007851]
largemem       up 1-00:00:00          1/5/0/6 nid[000101-000106]
lumid          up    4:00:00          1/6/1/8 nid[000016-000023]

Let’s pick one node on the interactive partition for 2 hours.

salloc --nodes=1 --time=02:00:00 --account=PROJECT_NAME --partition=interactive

Same as before, replace PROJECT_NAME with the project name that LUMI has provided you with.

salloc: Pending job allocation 7116989
salloc: job 7116989 queued and waiting for resources
salloc: job 7116989 has been allocated resources
salloc: Granted job allocation 7116989

As we see above, the allocation has been granted. To start the Jupyter Notebook on the compute node that we were allocated, we need the node name. This we can check with

squeue -u USER_NAME 

JOBID   PARTITION   NAME      USER       ST   TIME  NODES NODELIST(REASON)
7116989 interacti   interact  USER_NAME  R    2:14  1     nid002502

Our allocated node is called nid002502. This will be different for every allocation so remember to change it if your allocation runs out.

Starting a Jupyter server

Let’s start the Jupyter server on the supercomputer.

srun singularity exec -B /users/USER_NAME:/notebooks /scratch/PROJECT_NAME/jupyter-tunnel/base.sif jupyter lab --allow-root --ip 0.0.0.0 --notebook-dir /notebooks --NotebookApp.token='PASSWORD'

You must keep this terminal window running. Remember to change USER_NAME, PROJECT_NAME, and NOTEBOOK_PASSWORD to your own.

4 Create an SSH tunnel locally

The Jupyter server has now started. Now open a new local terminal window (not on the supercomputer) and run the following

ssh -v -N -L localhost:38888:NODE_NAME:8888 USER_NAME@lumi.csc.fi

With this command, we create a tunnel that communicates with the remote kernel on LUMI. We have chosen localhost:38888 as our local IP address. Remember to change NODE_NAME to the compute node that you got allocated. In our case it is nid002502. Both terminal windows need to keep running.

Now you can simply open JupyterLab by visiting http://localhost:38888 on your preferred browser.

You can work on this JupyterLab interface as you would on your local machine.

But let’s do a final test to make sure that we are running on the compute node that we allocated on LUMI. Let’s create a new notebook on our side menu called jupyter-test.ipynb. We can type the following command on a notebook cell and run it.

import os
os.system("hostname")

As we see, we get nid002502 which is the name of the node that we allocated with the salloc command.

Conclusion

In this tutorial, we gave you a brief idea of how you can use the flexibility of Jupyter Notebooks on a supercomputer. There are multiple variations depending on the architecture of the supercomputer, or different container modules. When in doubt, you can consult the documentation of the supercomputer you have access to, the system admin team, or, if you’re located in Europe, your local HPC competence centre such as ENCCS.

If you are working in a European company or organisation and interested in getting access to LUMI or any other EuroHPC JU supercomputer please check our Get Supercomputing Access page or contact us at info@enccs.se.