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Open OnDemand

Open OnDemand (OOD) gives you a complete web interface to CARC clusters — no SSH client, no X11 setup, just a browser. It is the easiest way to work on CARC systems if you are new to HPC or away from your usual machine.

Open the CARC OnDemand portal

Log in with your CARC username and password. If you don't have an account yet, start with Getting started at CARC.

What you can do in OnDemand

  • Files

    Browse your home, project, and scratch spaces; upload and download files; edit text files in the browser. For large transfers, prefer the command-line tools.

  • Cluster shell

    Open a login-node terminal in a browser tab — everything you can do over SSH, without an SSH client.

  • Jobs

    Compose, submit, and monitor Slurm jobs from a form-based interface, and inspect their output files when they finish.

  • Interactive apps

    Launch graphical and notebook sessions that run on compute nodes. The available apps depend on the cluster — check the Interactive Apps menu in the portal for the current list.

How interactive apps work

When you launch an interactive app, OnDemand submits a Slurm job on your behalf. That means:

  • You choose the resources (cores, memory, GPUs, walltime) in the launch form — the same considerations as any batch job apply, and the Good Neighbor Use Policy asks you not to leave hardware idle.
  • Your session may wait in the queue until resources are free, just like any other job. Small, short requests start faster.
  • The session ends when its walltime expires — save your work.
  • Usage counts against your project's fairshare like any other job.

When to use OnDemand vs. SSH

OnDemand is ideal for file management, quick edits, monitoring jobs, and interactive sessions. For long-running automated workflows, scripted submission, and bulk data movement, the command line remains the more powerful tool.