VS Code via Code-Server

This solution:#

Provides a method to connect VS Code to a compute node on klone, preserving the login nodes for the community. As a reminder, we prohibit users running processes on the login node.
Uses a server to develop and execute your code reducing battery usage. code-server handles the VSCode background processes, preventing them from slowing down your local machine.
Provides a simpler alternative to VS Code via ProxyJump, which requires a lot of setup and for Windows users requires 2-factor authentication to login and change directory.
Involves steps: pull the docker container, launch a batch job to start the container on a compute node, SSH tunnel to the compute node where the container is running, and securely access VS Code through your browser window.

Pull the Container#

This step only needs to be performed during the first set up.

Start an interactive job to pull the cointainer with the apptainer module. Here is an example command to start your interactive job:

salloc --account=uwit --partition=ckpt --cpus-per-task=1 --mem=16G --job-name=code-server --time=2:00:00

Loading the apptainer module is required.

module load apptainer

Pull the container from DockerHub. This will take a few minutes to complete. When complete, you will have a container image called code-server_lastest.sif. There are other versions of the container you might consider rather than the latest version: code-server tags.

apptainer pull docker://codercom/code-server

Launch code-server with SLURM#

Download the SLURM batch script.

wget https://hyak.uw.edu/files/code-server.job

Edit the job script (find comments "#update this line") to set your code-server session home directory and provide the name of the container if it does not match code-server_latest.sif, and edit the SBATCH directives as needed. The code block below shows the lines that should be updated as needed.

# Set home destination for code-server session
CODER_HOME="/gscratch/scrubbed/<UWNetID>" # update this line
# Provide container file
CODER_SIF="code-server_latest.sif" # update this line if needed

Submit the script with sbatch. This step launching of the code-server job script and all following steps will need to be repeated each time you log in and connect to VS Code.

sbatch code-server.job
Submitted batch job 17440706

This script will start a batch job and launch the code-server container. The SSH tunneling instructions, including the code-server session password, will be written to the output file (stdout) called code-server.job.<JobID> (code-server.job.17440706 in this example). Concatenate (cat) the output file for tunneling instructions. The following is an example output.

cat code-server.job.17440706
1. SSH tunnel from your workstation using the following command:

   ssh -N -L 8080:n3088:59985 <UWNetID>@klone.hyak.uw.edu

   and point your web browser to http://localhost:8080

2. log in to Code Server using the following credentials:

   password: +WwYzgh7YH/yHzUWNWNS

When done using Code Server, terminate the job by:

1. Sign out of Code Server (Find the three-lines icon Menu and select "Sign out of Code Server")
2. Issue the following command on the login node:

      scancel --name code-server

Monitor the job with squeue and your UWNetID like the following example.

squeue -u <UWNetID>
             JOBID PARTITION     NAME     USER ST       TIME  NODES NODELIST(REASON)
          17440706   compute code-ser  <UWNetID>  R       3:15      1 n3088

The output file (code-server.job.17440706 in this example) will also contain messages from code-server as the connection is established. These messages include:

The storage location of session associated files - ~/.local/share/code-server in your home directory.
The location of the configuration file for the session which contains the password that is also printed in the output file - ~/.config/code-server/config.yaml in your home directory.
Which IP and Port code-server HTTP and session is listening to.

As your session continues, more information will be printed to this output file.

Establish the SSH tunnel#

Follow the instructions in the output file. Open a new terminal/powershell/PuTTy window ON YOUR COMPUTER and use the command:

ssh -N -L 8080:n3088:59985 <UWNetID>@klone.hyak.uw.edu
... provide UWNetID password
... Duo 2 Factor Authentication

The login will appear to hang, but your connection is now open.

Open a new browser window to http://localhost:8080 and provide the password from the output file (code-server.job.17440706 in this example).

Provide Password

Extensions can be installed through the browser and will be stored in ~/.local/share/code-server/extensions in your home directory.

End the Session#

To end your session, find the three-lines icon Menu and select "Sign out of Code Server."

Sign Out

And end the batch job with scancel on klone like the following example.

scancel --name code-server

If you have trouble with this method, please report errors in an email to help@uw.edu with HYAK in the message.

Background Reading#

Coder Home

Code-server github repo

Code-server documentation

DockerHub page

Video explaining the benefits of Code-server