Unity Ondemand

Unity OnDemand

Use this skill for Unity's web UI. It is the right entry point when the user wants a browser shell, file transfer, a desktop session, or a hosted app/server launch.

When to use OnDemand

• Use OnDemand when the workflow is easier in a browser than over SSH.
• Use it for file browsing/transfers, getting a shell in a browser, opening a full Linux desktop, or launching Unity-hosted interactive apps.
• Use it when you want to stay out of the login-node workflow as much as possible and let the web UI handle the session entry point.
• If the task is specifically a notebook server, use the unity-jupyter subskill for launch tuning and kernel details.

How to think about it

• Browser shell: good for quick setup, inspection, and light coordination before handing off heavy work to Slurm.
• Desktop session: best when the workflow truly needs a full GUI, drag-and-drop file handling, or an application that behaves like a desktop app.
• App/server launch: best when the web UI can start the tool directly and the tool exposes its own browser interface.
• Prefer the lightest viable UI. Use a desktop only when the application really needs a desktop; otherwise use a browser app/server launch.

Unity-specific advice

• Unity's OnDemand is part of the ASC Unity experience and is meant to reduce friction for common HPC tasks without replacing Slurm.
• The important Unity OnDemand entry points to remember are Shell Access, Files, Unity Desktop, Unity Simple Desktop, Jupyter Notebook, and Matlab.
• If a browser-launched app needs more CPU, memory, GPU, or time than the default, choose the right resource request up front instead of relying on a retry.
• If a launch fails after a maintenance window or module change, suspect the module selection first, not the browser.
• For interactive compute work launched from OnDemand, keep the session bounded and remember that the resources still belong to the cluster scheduler.
• OnDemand can coexist with SSH-based workflows, but it is often the easier first step for people who do not want to manage shells and tunnels by hand.
• If you need a browser workflow on a remote machine, OnDemand is preferred over ad hoc desktop forwarding.

Good Defaults

• Choose a browser app launch if the work can stay in a browser.
• Choose Unity Desktop or Unity Simple Desktop if you need a full Linux desktop.
• Choose Jupyter Notebook through the unity-jupyter skill if the workflow is notebook-centric.
• Choose Matlab from Interactive Apps if the work is specifically MATLAB-centric.
• Escalate to batch or a dedicated interactive job if the web app is really just a front end for longer compute.