Interactive Sessions¶
CANFAR computing environments for astronomical research - Jupyter notebooks, and non-interactive applications.
🎯 Session Types Overview
Choose the right interface for your research:
- Jupyter Notebooks: Interactive data analysis and visualisation
- Desktop Environment: Full Linux desktop with GUI applications
- CARTA Viewer: Radio astronomy visualisation and analysis
- Firefly Viewer: Table and image viewing for surveys
- Contributed Apps: Specialised community applications
- Batch Processing: Automated and large-scale workflows
🚀 Session Fundamentals¶
What are Interactive Sessions?¶
Interactive sessions provide on-demand access to pre-configured computing environments running in containers. Each session type offers different interfaces optimized for specific astronomical workflows.
Key Benefits¶
- No Installation Required
- Access complex astronomy software through your web browser without local installation or configuration.
- Pre-Configured Environments
- Containers include popular astronomy packages like AstroPy, CASA, and scientific Python libraries ready to use.
- Persistent Data Access
- All sessions automatically connect to your ARC storage and can access VOSpace for long-term data management.
- Scalable Resources
- Choose flexible or fixed resource allocation based on your computational requirements.
📊 Session Type Comparison¶
| Session Type | Interface | Best For | GUI Support |
|---|---|---|---|
| Notebook | JupyterLab | Data analysis, prototyping, documentation | ✅ Web-based |
| Desktop | Full Linux desktop | CASA, image viewers, traditional software | ✅ Desktop GUI |
| CARTA | CARTA interface | Radio astronomy visualisation | ✅ Specialised |
| Firefly | Firefly viewer | Catalogue analysis, image display | ✅ Web-based |
| Contributed | Various | Specialised applications | ⚠️ Varies |
| Batch | None (headless) | Large-scale processing | ❌ Headless |
🔧 Session Management¶
Creating Sessions¶
- Via Science Portal:
- Launch sessions through the CANFAR Science Portal web interface with point-and-click simplicity.
- Via Command Line:
- Use the CANFAR CLI for scripted session creation and automation.
- Via Python API:
- Integrate session management into custom workflows using the CANFAR Python Client.
Session Lifecycle¶
- Creation (30 seconds - 3 minutes)
- Container download (first time) and startup with storage mounting
- Active Use
- Full access to computing resources and storage systems
- Idle Management
- Sessions automatically suspend after periods of inactivity to conserve resources
- Termination
- Container deletion with data preserved in persistent storage
Data Persistence
Important: Session containers are temporary. Always save important work to /arc/ storage or VOSpace before ending sessions.
📈 Resource Allocation¶
Flexible Allocation (Default)¶
Advantages: - Faster session startup - Can burst to higher resource usage when available - Optimal for interactive work and development
Best For: - Data exploration and analysis - Development and testing - Educational workshops
Fixed Allocation¶
Advantages: - Guaranteed consistent performance - Predictable resource availability - Better for production workloads
Best For: - Large-scale processing - Performance-critical analysis - Time-sensitive computations
Resource Selection Guide¶
| Workflow Type | Recommended Mode | CPU/Memory | Duration |
|---|---|---|---|
| Interactive Analysis | Flexible | 2-4 CPU, 4-8GB | Hours |
| Large Dataset Processing | Fixed | 4-8 CPU, 16-32GB | Hours-Days |
| Development & Testing | Flexible | 1-2 CPU, 2-4GB | Hours |
| Production Pipelines | Fixed | Varies by workload | Days |
🔗 Integration with Platform Services¶
Storage Integration¶
All interactive sessions automatically mount:
- ARC Home (
/arc/home/[user]/): Personal configurations and scripts - ARC Projects (
/arc/projects/[project]/): Shared research data and results - Scratch (
/scratch/): High-speed temporary storage for processing
Additional storage accessible via API:
- VOSpace (vos:): Long-term archives and data sharing
Container Environments¶
Sessions run in container environments that include:
- Operating system (typically Ubuntu Linux)
- Astronomy software packages (AstroPy, CASA, etc.)
- Scientific computing libraries (NumPy, SciPy, Matplotlib)
- Development tools and utilities
CVMFS Software Repositories¶
All CANFAR sessions provide access to read-only CVMFS (CernVM File System) software repositories. This feature provides instant access to the vast collections of pre-built scientific software maintained by the Digital Research Alliance of Canada (Alliance).
See the Software Repositories (CVMFS) guide for more information and examples.
Authentication & Permissions¶
Sessions inherit your CANFAR permissions:
- Automatic access to your group projects
- Secure integration with CADC services
- API access for automated workflows
🎯 Choosing Your Session Type¶
For Data Analysis¶
- New to CANFAR? → Start with Jupyter Notebooks
- Familiar interface combining code, documentation, and visualisation
- Need GUI Applications? → Use Desktop Sessions
- Full Linux desktop for CASA, image viewers, and traditional software
For Astronomy Specialisations¶
- Radio Astronomy → CARTA Viewer
- Optimized for radio interferometry data visualisation and analysis
- Survey Data → Firefly Viewer
- Efficient table and image viewing for large astronomical catalogues
- Specialised Tools → Contributed Applications
- Community-maintained applications for specific research domains
For Production Work¶
- Large-Scale Processing → Batch Sessions
- Automated workflows for processing large datasets without interactive interfaces
API Access to Sessions¶
If you have a session running and it exposes an API, you can programatically interact with it remotely, either from another session or from your laptop.
The base of the session API will be available at the session URL. For more details, consult the API docs for each of the session types: - CARTA API Docs - Firefly API Docs - JupyterLab API Docs