OnDemand Portal Orientation

Callout

Pomona College HPC Workshop Series

This workshop is part of the Pomona College Research Computing Workshop Series, focused on the Open OnDemand web portal for the Sagehen HPC cluster.

Cluster: sagehen.hpc.pomona.edu Web Portal: OnDemand Support: its-hpc@pomona.edu

Access Sagehen’s compute resources, Jupyter notebooks, RStudio, and virtual desktops through your web browser : no SSH required.

Developed for Pomona College by Andrew Wilson, ITS Research Computing. Licensed under CC-BY 4.0.

Welcome to the OnDemand Portal Orientation workshop! This training teaches you how to access Sagehen HPC resources through a web browser interface without requiring SSH knowledge.

What You Will Learn

---

In this workshop, you will:

• Navigate the OnDemand portal and understand its layout
• Upload, download, and manage research data through a graphical interface
• Access command-line shell through your web browser
• Launch interactive Jupyter notebooks and RStudio for data analysis
• Submit batch computing jobs to the cluster
• Monitor job progress and retrieve results

Workshop Overview

---

This is a beginner-friendly introduction to OnDemand, designed for users new to HPC who prefer graphical interfaces over command-line tools.

Episode 1: What is OnDemand?

Learn why OnDemand is valuable and how it differs from traditional SSH access.

Episode 2: Dashboard Navigation

Explore the main interface and find key menu items and settings.

Episode 3: File Manager

Manage your data files, understand storage locations, and transfer files.

Episode 4: Shell Access

Use the web terminal for command-line computing when needed.

Episode 5: Interactive Applications

Launch Jupyter notebooks and RStudio directly from your browser.

Episode 6: Job Management

Submit batch jobs and monitor their progress without writing SLURM scripts.

Time Requirements

---

• Total workshop time: Approximately 2.5 hours
• Each episode: 20-30 minutes including exercises
• Hands-on exercises: 15 minutes per episode

Prerequisites

---

Before starting this workshop, ensure you have:

1. Pomona College account credentials
2. DUO Multi-Factor Authentication configured
3. Active HPC account approved by your PI
4. Web browser (Chrome, Firefox, Safari, or Edge)
5. Internet connection stable enough for interactive applications

Prerequisite

What You Need Before Starting

• Valid @pomona.edu username and password (not email format)
• DUO authentication configured (mobile app or SMS phone number)
• Approved HPC account on Sagehen cluster
• Modern web browser (Chrome, Firefox, Safari, or Edge, updated within 6 months)
• Stable broadband internet connection (minimum 2 Mbps recommended)

If you’re missing any of these, contact its-hpc@pomona.edu to request setup before the workshop.

Getting Started

---

1. Open a web browser
2. Navigate to https://ondemand.hpc.pomona.edu/
3. Log in with your Pomona username
4. Complete DUO MFA verification
5. Welcome to OnDemand!

Need Help?

---

• Technical Issues: Email its-hpc@pomona.edu
• Quick Questions: Contact Andrew Wilson (Instructor)
• Documentation: OnDemand has built-in help at https://ondemand.hpc.pomona.edu/

Workshop Content

---

This workshop uses the Carpentries Workbench format with: - Clear learning objectives for each episode - Hands-on challenges with solutions - Real Sagehen examples and commands - Best practices and troubleshooting tips

Let’s get started with Episode 1!

Acknowledgments

---

Developed by Andrew Wilson, Director of Research Computing and Digital Scholarship at Pomona College, with Andrei Motchenko, who tested, edited and produced screenshots for the workshop series.

	Setup Instructions	Download files required for the lesson
Duration: 00h 00m	1. What is OnDemand?	What is OnDemand and why use it? How does OnDemand differ from SSH? What are the benefits for HPC users? ::::::::::::::::::::::::::::::::::::::::::::::::
Duration: 00h 20m	2. Logging In and Dashboard Overview	How do you log into OnDemand? What does the dashboard look like? How do you navigate between sections? Where can you find session and account information? ::::::::::::::::::::::::::::::::::::::::::::::::::
Duration: 00h 40m	3. Navigating Storage Locations	What storage locations are available on Sagehen HPC? How do /rhome and /bigdata differ from /scratch and /tmpfs? What are the capacity limits for each storage location? When should you use each storage location? ::::::::::::::::::::::::::::::::::::::::::::::::::
Duration: 00h 55m	4. Uploading, Downloading, and Editing Files	How do you upload files to Sagehen HPC through OnDemand? How do you download files back to your local computer? How do you create, rename, move, and delete files? Can you edit files directly in the browser? ::::::::::::::::::::::::::::::::::::::::::::::::::
Duration: 01h 20m	5. Shell Access and Command-Line Computing	How do you access the command line through OnDemand? What is a Web Terminal session? How do you manage multiple terminal sessions? What commands are available in OnDemand shell access? ::::::::::::::::::::::::::::::::::::::::::::::::
Duration: 01h 55m	6. Launching Jupyter Notebooks	How do you launch a Jupyter notebook from OnDemand? How do you configure resources for your notebook session? How do you use notebook cells, run code, and write documentation? How do you install additional Python packages? ::::::::::::::::::::::::::::::::::::::::::::::::::
Duration: 02h 20m	7. RStudio and GPU Resources	How do you launch RStudio from OnDemand? What is the RStudio interface layout? How do you request GPU resources for interactive apps? How do you verify GPU access in Jupyter or R? ::::::::::::::::::::::::::::::::::::::::::::::::::
Duration: 02h 45m	8. Submitting Batch Jobs	How do you submit batch jobs through OnDemand? What is the difference between Quick Submit and uploading a script? How do you write a basic SLURM job script? How do you submit GPU jobs and job arrays? ::::::::::::::::::::::::::::::::::::::::::::::::::
Duration: 03h 10m	9. Monitoring Jobs and Troubleshooting	How do you monitor running jobs in OnDemand? Where do you find job output and error logs? How do you debug a failed job? What are typical queue wait times and job limits? ::::::::::::::::::::::::::::::::::::::::::::::::::
Duration: 03h 35m	Finish

The actual schedule may vary slightly depending on the topics and exercises chosen by the instructor.

Setup

Before the Workshop

System Requirements

You need:

• Web browser: Chrome, Firefox, Edge, or Safari (recent version recommended - updated within last 6 months)
• Internet connection: Stable, broadband recommended (minimum 2 Mbps for file uploads)
• Pomona College account: Active @pomona.edu email and password
• DUO Multi-Factor Authentication: Either mobile app or phone number for SMS codes
• No SSH needed! OnDemand is entirely web-based

Browser Compatibility

OnDemand works best on: - Chrome/Chromium (version 90+) - Firefox (version 88+) - Safari (version 14+) - Edge (version 90+)

If you experience issues, try a different browser.

Preparing Your Computer

1. Update your browser to the latest version
   • Click Help menu → About [Browser Name]
   • It will automatically update if available
2. Test your internet connection
   • OnDemand requires stable connection
   • Upload and download speeds matter for file transfers
   • Contact your IT if you have slow/unstable WiFi
3. Have your Pomona credentials ready (username and password)
   • You’ll use these to log into OnDemand
   • Example username: alice (not alice@pomona.edu)
4. Set up DUO MFA if not already done:
   • Go to https://duo.pomona.edu
   • Log in with Pomona username and password
   • Follow DUO setup instructions
   • Choose: Download Duo Mobile app OR register phone number for SMS
   • Recommended: Use Duo Mobile app for most reliable authentication

What is OnDemand?

OnDemand is a web-based interface to HPC resources. You get: - File management (upload, download, organize) - Interactive applications (Jupyter notebooks, RStudio) - Job submission and monitoring - Web terminal (if you need command-line access) - No need to learn SSH or install special software

OnDemand runs on Sagehen HPC cluster at Pomona College. All your regular HPC storage and jobs are accessible through the web interface.

Accessing OnDemand

1. Open your web browser
2. Navigate to: https://ondemand.hpc.pomona.edu/
3. You should see a login screen titled “Sagehen OnDemand Portal”
4. Enter your Pomona credentials
5. Complete DUO authentication
6. You’ll see the OnDemand dashboard

If you see an error: - Check that URL is correct (note the “s” in https) - Clear browser cache (Ctrl+Shift+Delete or Cmd+Shift+Delete) - Try a different browser - Check internet connection

Test Your Access Before Workshop

Complete this checklist before the workshop to ensure everything works:

• Successfully log into OnDemand
• See the main dashboard (Files, Jobs, Apps menu)
• Can access Files → Home Directory
• Can access Interactive Apps → Web Terminal
• DUO authentication completes quickly
• Dashboard loads within 5 seconds

If any item is unchecked, troubleshoot before the workshop (see Troubleshooting section below).

What to Bring

• Working laptop or desktop computer (not just a tablet)
• Notes or questions about your research data or computing needs
• Sample files to practice uploading (optional, 1-100 MB)
• Questions! This is an interactive workshop

Pre-Workshop Checklist

Checklist

Account & Authentication

• I have an active Pomona (@pomona.edu) email account
• I know my Pomona username (the part before @pomona.edu)
• I’ve set up or can access my DUO account
• I can log into Pomona email or Canvas successfully

Browser & Computer

• My web browser is updated (within last 6 months)
• My computer has reliable internet connection
• I’ve tested OnDemand access at least once
• I can access OnDemand dashboard

HPC Account

• I have an HPC account on Sagehen (ask its-hpc@pomona.edu if unsure)
• My account is active (not suspended)
• I know my Pomona username for OnDemand login

Troubleshooting Pre-Workshop

Problem	Solution
“Authentication failed”	Verify Pomona username (not email). Try password reset at https://duo.pomona.edu
DUO request appears but I don’t approve it	Deny the request. Try logging in again. If repeated denials, contact its-hpc@pomona.edu
Browser shows “Connection refused” or similar	Check internet connection. Try different browser. Clear cache (Ctrl+Shift+Delete)
“Connection timed out”	Try again later. OnDemand may be under maintenance. Check https://www.pomona.edu/its/ for status
OnDemand loads but is very slow	This is normal during peak hours (9am-5pm weekdays). Try again in evening or early morning
Can’t find OnDemand URL or it’s blocked	Contact your network admin if on institutional network. You may need VPN if off-campus

Getting Help Before the Workshop

If you encounter issues:

• Account/Pomona credentials: Contact ITS Help Desk (see directory)
• DUO setup or problems: Contact ITS Help Desk
• OnDemand access issues: Email its-hpc@pomona.edu
• No HPC account yet: Email its-hpc@pomona.edu to request one

Include in your email: - What you’re trying to do - What error message you see (screenshot helpful) - When it happens - What you’ve already tried

Notes for This Workshop

• Duration: about 3.5 hours
• Level: No prior HPC or command-line experience needed
• Format: Interactive hands-on with live demonstrations
• Outcome: You’ll be comfortable using OnDemand for file management, running interactive applications, and submitting jobs

Questions Before Starting?

Email: its-hpc@pomona.edu Instructor: Consult workshop schedule Documentation: https://www.pomona.edu/its/

Welcome to the workshop!