Open OnDemand

Overview

Teaching: 10 min
Exercises: 10 min

Questions

• How do we use Open OnDemand?

Objectives

• Open a shell session in your web browser

• Start an interactive Desktop session

• Start an interactive JupyterLab session

Open OnDemand is an open-source web portal developed by Ohio Supercomputer Center that enables researchers to access HPC systems from their web browsers. In the previous section we showed how the FarmShare OnDemand File Manager can be used to access, edit, and transfer data on an HPC filesystem. FarmShare OnDemand also allows you to access a FarmShare shell, start an interactive desktop session, and use interactive apps like JupyterLab, RStudio, Matlab, and VS Code.

To access the FarmShare OnDemand Dashboard, open your web browser and go to http://ondemand.farmshare.stanford.edu.

Access a FarmShare Shell

You can access a FarmShare by selecting Clusters > FarmShare Shell Access from the top menu of the OnDemand Dashboard.

A new window will open in your browser, and you will automatically be logged onto a FarmShare login node. This will work just like the shell session in your local terminal app, but you don’t need to log in with SSH or authenticate with Duo Two-Factor authentication.

X11 Forwarding

X11 forwarding does not work with the OnDemand shell. If you need to use software with X11, you can continue to use your local terminal app or you can use an interactive desktop session.

Start an Interactive Desktop Session

The FarmShare Desktop session launches an interactive desktop on one or more compute nodes, granting full access to the resources those nodes provide. This is similar to an interactive job (srun --pty bash), with the added bonus of a graphical user interface (GUI).

1. From the OnDemand Dashboard, select Interactive Apps > FarmShare Desktop.
2. In the screen that opens, specify the Size (number of cores and memory), whether to Allocate a GPU, and the Number of hours that the session should run for.
3. Click the Launch button.
4. The My Interactive Sessions page will open. You will see a card for your pending FarmShare Desktop session. Once the resources have been allocated, you can click the Launch FarmShare Desktop button to open the desktop session.

Start an Interactive JupyterLab Session

FarmShare OnDemand allows users to launch common software GUIs in a web browser, powered by the compute resources that you request. Currently available interactive apps include JupyterLab, MATLAB, RStudio, and VS Code.

We will only cover how to start a JupyterLab session, but the process is largely the same for the other apps.

1. From the OnDemand Dashboard, select Interactive Apps > JupyterLab.
2. In the screen that opens, specify the Python version, Size (number of cores and memory), whether to Allocate a GPU, and the Number of hours that the session should run for.
3. Click the Launch button.
4. The My Interactive Sessions page will open. You will see a card for your pending JupyterLab session. Once the resources have been allocated, you can click the Connect to Jupyter button to open the session.

Key Points

• Open OnDemand allows users to interface with an HPC system through a web browser.