Open OnDemand¶

Open OnDemand is a web-based interface that provides easy access to DelftBlue resources through your browser. It allows you to manage files, submit jobs, run interactive applications, and access a remote desktop without the need for SSH command-line tools.

Accessing Open OnDemand¶

The Open OnDemand portal is available at:

https://login.delftblue.tudelft.nl/

Login¶

1. Navigate to https://login.delftblue.tudelft.nl/
2. Sign in with your TU Delft NetID and password
3. You will be redirected to the Open OnDemand dashboard

Features¶

File Management¶

The Files menu provides a web-based file browser for your DelftBlue directories:

• Browse your /home and /scratch directories
• Upload and download files through the browser
• Create, rename, and delete files and folders
• Edit text files directly in the browser
• View file permissions and properties

Shell Access¶

Open a terminal directly in your browser by clicking "Clusters" → "DelftBlue Shell Access". This provides the same command-line interface as SSH, but accessible through the web browser.

Job Management¶

Monitor and manage your Slurm jobs through the web interface:

• View active jobs
• Check job status and queue position
• View job output and error logs
• Cancel running jobs

Interactive Applications¶

Open OnDemand provides easy access to interactive applications. From the "Interactive Apps" menu, you can launch:

DelftBlue Desktop¶

A full remote desktop session running on a DelftBlue visualisation node:

1. Select "Interactive Apps" → "DelftBlue Desktop"
2. Fill in the form:
   • Account (e.g., research-<faculty>-<department>)
   • Runtime [h] (maximum 4 hours)
   • Extra arguments for Slurm — the CPU and memory request, e.g. --ntasks=1 --cpus-per-task=8 --mem-per-cpu=2G. The form has no separate cores/memory fields, and the job is rejected if these are missing.
3. Click "Launch"
4. Wait for the job to start (it enters the queue like a normal Slurm job)
5. Click "Launch DelftBlue Desktop" when the session is ready
6. Access your desktop directly in the browser

From the desktop, you can:

• Open a terminal
• Load software modules
• Run graphical applications (MATLAB, ParaView, etc.)

Graphical applications render with software OpenGL (Mesa); vglrun is not available. For more information, see the visualisation nodes documentation.

JupyterLab (Apptainer)¶

Launch Jupyter Lab or Jupyter Notebook sessions with specialised environments:

1. Select "Interactive Apps" → "JupyterLab (Apptainer)"
2. Choose from multiple pre-configured environments:
   • PyTorch with CUDA support - For deep learning with GPU acceleration
   • TensorFlow with CUDA support - Machine learning with GPU support
   • Multi-language data science - Python, R, and Julia in one environment
   • PySpark - For big data processing
   • Minimal installation - Lightweight environment for basic tasks
3. Configure your session (cores, memory, time, GPU if needed)
4. Launch and access Jupyter directly in your browser

For detailed information on using Jupyter on DelftBlue, see the Jupyter documentation.

MATLAB¶

Run MATLAB with full GUI support in your browser:

1. Select "Interactive Apps" → "MATLAB"
2. Configure your Slurm settings (account, cores, memory, time)
3. Launch the session
4. Access MATLAB with full GUI support in your browser

The MATLAB application provides a complete desktop environment optimised for computational work.

ParaView¶

Scientific visualisation with GPU-accelerated rendering:

1. Select "Interactive Apps" → "ParaView"
2. Configure your session settings
3. Launch with EGL containers for hardware-accelerated GPU rendering
4. Access ParaView directly in your browser

ParaView on Open OnDemand uses GPU acceleration for high-performance visualisation of large scientific datasets.

RStudio (Apptainer)¶

Run RStudio Server with multiple R versions available:

1. Select "Interactive Apps" → "RStudio (Apptainer)"
2. Choose your preferred R version
3. Configure your session (cores, memory, time)
4. Launch and access RStudio in your browser

RStudio Server provides a familiar IDE for R programming and statistical computing.

VS-Code (Apptainer)¶

Web-based VS Code for development directly on DelftBlue:

1. Select "Interactive Apps" → "VS-Code (Apptainer)"
2. Configure your session settings
3. Launch and access VS Code in your browser
4. Edit code, run terminals, and use extensions

VS Code Server provides a full-featured development environment without needing to install anything locally.

Advantages of Open OnDemand¶

• No SSH client needed: Access DelftBlue from any device with a web browser
• User-friendly interface: Ideal for users less familiar with command-line tools
• File management: Easy drag-and-drop file uploads and downloads
• Interactive applications: Launch graphical applications without setting up X11 forwarding or VNC
• Cross-platform: Works on Windows, macOS, Linux, and even tablets

Limitations¶

• File uploads through the browser have size limitations (for large datasets, use SCP/SFTP or other transfer methods)
• Some advanced SSH features (like SSH key forwarding) are not available
• Interactive desktop sessions are limited to 4 hours maximum
• Desktop sessions render with software OpenGL (Mesa); for GPU-accelerated visualisation use the dedicated ParaView Interactive App

Getting Help¶

If you encounter issues with Open OnDemand, please contact the DelftBlue support team. For general help with DelftBlue, see the Frequently Asked Questions.