Code Editors¶

NHR@KIT systems support several IDEs and code editors for remote development via SSH.

Visual Studio Code¶

Visual Studio Code (VS Code) is an open source code editor from Microsoft. It has become one of the most popular IDEs and can be extended with plugins for language support, debugging, and remote development. VS Code can be installed locally on Windows, macOS, and Linux.

Remote - SSH extension¶

The Remote - SSH extension allows you to connect your locally installed VS Code to the remote login nodes. Unlike graphical remote desktop sessions (RDP, VNC), this approach has no lag or font rendering issues.

Installation¶

Click the Extensions button in the left sidebar, search for remote ssh, and install Remote - SSH.

Configuration¶

Open the Remote Explorer. On Linux and macOS, ~/.ssh/config is evaluated automatically and existing SSH targets appear in the sidebar.

To add a new target, click the + symbol. Make sure SSH Targets is selected in the Remote Explorer dropdown. Enter the connection details as username@hostname.

Connecting¶

Open the Remote Explorer, right-click a target, and choose Connect in Current Window or Connect in New Window. Enter your OTP and service password when prompted.

Once connected, open a project directory with Ctrl+K Ctrl+O.

Extensions installed locally are not automatically installed on the remote. Open the Extensions panel during a remote session and VS Code will offer to install them remotely.

Disconnecting¶

Click the green indicator in the lower-left corner and select Close Remote Connection. Simply closing the VS Code window leaves server-side components running on the login node.

Access to compute nodes¶

VS Code Tunnels¶

code-server¶

code-server runs the VS Code server on any machine and makes it accessible in a web browser. This enables development and debugging on compute nodes, including GPU nodes.

code-server is available via Lmod: module load code-server

Starting code-server¶

code-server can run on login nodes or compute nodes. The example below starts an interactive job on a GPU partition:

salloc -p accelerated --gres=gpu:4 --time=30:00  # start interactive job
module load code-server                            # load module

Specify a port in the unprivileged range (above 1024). If the port is already in use, choose another one. Set a password via the PASSWORD environment variable or in ~/.config/code-server/config.yaml:

PASSWORD=<mySecret> \
    code-server \
      --bind-addr 0.0.0.0:8081 \
      --auth password

Connecting to code-server¶

Create an SSH tunnel from your local machine to the node running code-server:

ssh -L 8081:<computeNodeID>:8081 username@hk2-x86.scc.kit.edu

Replace <computeNodeID> with the node running your job. If code-server is running on a login node, use localhost.

Open http://127.0.0.1:8081 in your browser. The login page will appear:

Enter the password from ~/.config/code-server/config.yaml or the PASSWORD variable. The familiar VS Code interface will open:

Ending the session¶

To log out temporarily, open the Application Menu in the left sidebar and click Log out.

To terminate the session, cancel the interactive Slurm job with Ctrl+C.

Zed¶

Zed is a high-performance code editor with built-in SSH remote development — no extension required. The UI runs locally while language servers, tasks, and terminals run on the remote host.

To connect, open the Remote Projects dialog (Ctrl+Shift+Alt+O on Linux), click Connect New Server, and enter the SSH connection string (e.g. username@hk2-x86-login.scc.kit.edu). Zed shells out to the ssh binary and honours ~/.ssh/config, so existing SSH targets work out of the box.

On first connect, Zed downloads a small headless server binary to ~/.zed_server/ on the login node. If the compute cluster has no outbound internet access, enable "upload_binary_over_ssh": true in your Zed settings to have Zed download the binary locally and upload it over SSH instead.

See the Zed remote development documentation for full configuration options including port forwarding and proxy settings.

SSH tunnel to compute nodes¶

Login nodes cannot be used as proxy jump hosts, so IDEs that rely on SSH (VS Code Remote - SSH, Zed, etc.) cannot connect directly to compute nodes by default. The script start-vscode-remote-ssh.sh works around this for any SSH-capable IDE.

Run it on the login node: it submits an interactive Slurm job, starts an unprivileged sshd on the allocated compute node, and prints everything you need — including a one-time setup guide (SSH key generation, ~/.ssh/config snippet) and a ready-to-paste tunnel command for each session.

Usage¶

Step 1 — Start the script on the login node:

ssh -t username@hk2-x86-login.scc.kit.edu start-vscode-remote-ssh.sh

The script submits a job, waits for the node to become available, starts sshd, and prints the tunnel command. To target a specific partition (e.g. GPU), pass --partition:

ssh -t username@hk2-x86-login.scc.kit.edu start-vscode-remote-ssh.sh --partition gpu-h200 --gres=gpu:1

Keep this terminal open for the duration of your session. Press Ctrl+C here to terminate the job and sshd.

Step 2 — Open the SSH tunnel in a new local terminal:

Copy the tunnel command from the script output and run it (the node name and port are session-specific — the example below is for illustration only):

ssh -N -L 22222:<node>:22222 username@hk2-x86-login.scc.kit.edu

Keep this terminal open while you work. The tunnel must stay alive.

Step 3 — Connect your IDE:

In VS Code, open the Remote Explorer and connect to the host defined in the ~/.ssh/config snippet printed by the script (vscode-hk2 by default). The tunnel routes you transparently to the compute node.

To verify that everything is working as expected, simply type ssh vscode-hk2 in a local terminal. You should now be logged in to a compute node.

sacctmgr modify user $USER set defaultaccount=PROJECT