VS Code¶

VS Code reaches Hydra three ways. Remote-SSH connects the VS Code on your own machine to a login node, which is fine for editing files and nothing more. The login-node limits apply to anything it runs. The other two run VS Code itself on a compute node and show it in your browser, through an ssh tunnel or through a tunnel that Microsoft relays.

Way	Where VS Code runs	Needs	Use for
Remote-SSH	your machine; a helper on a login node	the Remote-SSH extension	editing files; nothing that computes
VS Code server	a compute node, shown in your browser	an ssh tunnel from your machine	any interactive work
VS Code tunnel	a compute node, shown in your browser	a GitHub account; no ssh tunnel	the same, and from telework.si.edu

The tools/vscode module also provides vscode-desktop, a windowed VS Code over X11, which needs an X server that supports it and is slow. The module's start-vscode script offers desktop, server and tunnel at a prompt.

Use Remote-SSH from your own VS Code¶

Install VS Code and the Remote-SSH extension on your machine.
Remote-SSH: Connect to Host, enter [email protected], and log in with your Hydra password.

Remote-SSH runs its helper on a login node

Anything you start from its terminal is under the login-node limits. For anything that computes, submit a job or open an interactive session.

Start a VS Code server on a compute node¶

On a login node, start an interactive session, then load the module and start the server:

$ qrsh
$ module load tools/vscode
$ start-vscode-server
start-vscode-server: starting vscode server on host=compute-64-15 IP=192.168.92.85 and port=8000
  you need to create a ssh tunnel on your local machine with
    ssh -N -L 8000:192.168.92.85:8000 [email protected]
  in a terminal window.
...
Web UI available at http://192.168.92.85:8000?tkn=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

The script prints the tunnel command and waits. Press Enter to start the server, or start the script with -no-pause to skip the wait. The token changes every start. -token STRING fixes it and -no-token removes it. start-vscode-server -help lists the options.

On your own machine, open the tunnel the script printed, in a terminal you leave alone:
```
$ ssh -N -L 8000:192.168.92.85:8000 [email protected]
```
In a browser, open http://localhost:8000?tkn=TOKEN with the token from step 1. Use localhost. The 192.168.… address the server prints is reachable only inside the cluster.
When done, Ctrl-C in the server's window, Ctrl-C in the tunnel's terminal, then exit the session.

Use a VS Code tunnel¶

A tunnel registers the compute node with Microsoft's relay under a name, and you open vscode.dev with that name. It needs a GitHub account for authentication. SI Microsoft accounts fail because of SI's MFA setup.

In an interactive session, load the module and start the tunnel:

$ qrsh
$ module load tools/vscode
$ start-vscode-tunnel
start-vscode-tunnel: starting a tunnel, name: USERNAME-compute-64-15
  to access the tunnel, point your browser to https://vscode.dev/tunnel/USERNAME-compute-64-15 on your local machine.
...
? How would you like to log in to Visual Studio Code? ›
   Microsoft Account
[] GitHub Account
To grant access to the server, please log into https://github.com/login/device and use code ABE4-F1A6

Press Enter when the script asks, to start the tunnel. Then choose GitHub Account with the arrow keys, open the device-login URL in a browser, and enter the code.
Open https://vscode.dev/tunnel/USERNAME-compute-64-15 in a browser. Choose GitHub if it asks how to authenticate.
When done, Ctrl-C in the tunnel's window, then exit the session.

If the tunnel fails at start with error failed to lookup tunnel: connection error, run host use.rel.tunnels.api.visualstudio.com once, which returns an address, and start the tunnel again. To reset the stored credentials, delete ~/.vscode/cli/token.json.

VS Code¶

Use Remote-SSH from your own VS Code¶

Start a VS Code server on a compute node¶

Use a VS Code tunnel¶

Further reading¶