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Remote Development on OSC

Visual Studio Code's Remote-SSH extension allows you to develop on OSC as if you were working locally. This guide shows you how to set it up and use it effectively.

Prerequisites

Initial Setup

Make sure the Remote-SSH extension is installed and your SSH config is set up.

Connecting to OSC

Method 1: Command Palette

  1. Press Ctrl+Shift+P (or Cmd+Shift+P on macOS)
  2. Type "Remote-SSH: Connect to Host"
  3. Select pitzer (or owens) from your SSH config
  4. A new VS Code window opens connected to OSC

Method 2: Remote Explorer

  1. Click the Remote Explorer icon in the sidebar (><)
  2. Select "SSH Targets" from dropdown
  3. Click the connect icon next to pitzer

Method 3: Command Line

code --remote ssh-remote+pitzer /path/to/directory

First Connection

On your first connection: 1. VS Code downloads the VS Code Server to OSC 2. This takes 1-2 minutes 3. A progress notification appears in the bottom-right 4. Future connections are much faster

Installing Extensions Remotely

Extensions you use locally should also be installed on the remote server. Open the Extensions view (Ctrl+Shift+X) and click "Install in SSH: pitzer" for each extension you need. For recommended extensions, see VS Code Extensions.

File Transfer

VS Code supports drag-and-drop uploads and right-click downloads for small files. For bulk transfers, see the File Transfer Guide.

Port Forwarding

Access web services running on OSC (Jupyter, TensorBoard, etc.):

Automatic Port Forwarding

VS Code automatically detects and forwards ports:

  1. Start a service on OSC (e.g., Jupyter on port 8888)
  2. VS Code detects it and shows a notification
  3. Click "Open in Browser"

Manual Port Forwarding

  1. Click "PORTS" tab in bottom panel (next to Terminal)
  2. Click "Forward a Port"
  3. Enter port number (e.g., 8888)
  4. Access at http://localhost:8888

Example: Jupyter Notebook

# In VS Code terminal on OSC
module load python/3.12
jupyter notebook --no-browser --port=8888

VS Code forwards port 8888 automatically. Click the link or open localhost:8888 in your browser.

Running Code

Python Scripts

Method 1: Terminal

python script.py

Method 2: Run Button

  • Open a Python file
  • Click the "Run" button (▶️) in the top-right
  • Or press Ctrl+Alt+N (if Code Runner extension installed)

Jupyter Notebooks

  1. Open .ipynb file in VS Code
  2. Select Python kernel (from OSC)
  3. Run cells with Shift+Enter

All execution happens on OSC!

Debugging

Set breakpoints and debug remotely:

  1. Set breakpoints by clicking left of line numbers
  2. Press F5 to start debugging
  3. Use Debug Console to inspect variables
  4. All debugging runs on OSC

Best Practices

1. Use Login Nodes Appropriately

Login nodes (where Remote-SSH connects) are shared among all users. They are fine for:

  • Editing code, browsing files, git operations
  • Submitting jobs (sbatch, sinteractive)
  • AI coding tools (Claude Code, Copilot) — these are network-bound, not CPU-bound
  • Quick pip install or uv add

DO NOT run intensive computations on login nodes: long-running scripts, large builds, pytest on big test suites, or anything GPU-related.

2. Use Compute Nodes for Heavy Work

Use sinteractive to get your own compute node from the VS Code terminal:

# CPU-only (for builds, tests, preprocessing)
sinteractive -A PAS1234 -c 4 -t 02:00:00

# With GPU (for training, debugging GPU code)
sinteractive -A PAS1234 -c 4 -g 1 -t 01:00:00

Your home directory is the same NFS mount on both login and compute nodes — same files, same paths. No need to copy anything. When done, type exit to release the node.

For longer unattended runs, use batch jobs:

sbatch job_script.sh

For full details, see the Interactive Sessions section of the Job Submission Guide.

3. Save Regularly

Although Remote-SSH is reliable: - Enable auto-save: "files.autoSave": "afterDelay" - Commit to Git frequently - Keep backups of important work

4. Manage Extensions

  • Only install necessary extensions remotely
  • Some extensions can slow down remote connections
  • Disable unused extensions

5. Handle Disconnections Gracefully

If connection drops: - VS Code tries to reconnect automatically - Unsaved changes are usually preserved - Terminal sessions may be lost (use tmux or screen for persistence)

Advanced Tips

Using tmux for Persistent Sessions

# Start tmux session
tmux new -s work

# Detach: Ctrl+b, then d
# Reattach: tmux attach -t work

This keeps your session alive even if VS Code disconnects.

Workspace Settings for Remote

Create .vscode/settings.json in your project:

{
  "python.defaultInterpreterPath": "${workspaceFolder}/.venv/bin/python3",
  "python.terminal.activateEnvironment": true,
  "terminal.integrated.env.linux": {
    "PATH": "${workspaceFolder}/.venv/bin:${env:PATH}"
  }
}

If using legacy pip+venv with ~/venvs/, replace .venv paths with ${HOME}/venvs/myproject.

SSH Config for Multiple Login Nodes

# Primary login
Host pitzer
    HostName pitzer.osc.edu
    User your.osuusername

# Specific login node (if needed)
Host pitzer01
    HostName pitzer-login01.osc.edu
    User your.osuusername

Troubleshooting

Connection Hangs

Problem: "Setting up SSH Host..." hangs indefinitely

Solutions: 1. Check OSC system status 2. Verify SSH connection works: ssh pitzer 3. Delete remote VS Code server: 

ssh pitzer
rm -rf ~/.vscode-server
4. Reconnect in VS Code

Extension Installation Fails

Problem: Extensions won't install on remote

Solutions: 1. Check disk quota: quota -s on OSC 2. Clear extension cache: 

rm -rf ~/.vscode-server/extensions
3. Reinstall extensions one by one

Python Interpreter Not Found

Problem: VS Code can't find Python

Solutions: 1. Load Python module in terminal: 

module load python/3.12
which python3
2. Set interpreter in VS Code: - Ctrl+Shift+P → "Python: Select Interpreter" - Enter the path from which python3

Terminal Not Loading

Problem: Integrated terminal fails to start

Solutions: 1. Check your shell configuration (~/.bashrc) 2. Simplify .bashrc (remove complex startup scripts) 3. Try setting the default profile: "terminal.integrated.defaultProfile.linux": "bash"

Port Forwarding Not Working

Problem: Can't access forwarded ports

Solutions: 1. Verify service is running: netstat -tuln | grep <port> 2. Manually add port in VS Code Ports panel 3. Check firewall settings on OSC

Performance Tuning

Reduce remote extension count — install only essentials remotely:

  • ms-python.python
  • ms-python.vscode-pylance
  • ms-toolsai.jupyter

Exclude large directories from the file watcher in .vscode/settings.json:

{
  "files.watcherExclude": {
    "**/node_modules": true,
    "**/.git": true,
    "**/data": true,
    "**/checkpoints": true
  }
}

Next Steps

Resources