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Visual Studio Code is usually started on a localhost, which results in starting a local application to interact with the GUI.

On Ares and Athena, we cannot easily expose the GUI to the external world, as calculations are done internally on a computing node, not visible from the Internet.

Therefore, in ACC Cyfronet we have prepared start-vscode-web  a script that can be used easily with the VSCode module. In this guide, we will explore how to use it to start a VSCode web session. 

How to use on Ares?

Via SSH tunnel

The trick is to start the VSCode webserver via a job submitted to a computing node and creating a create an SSH tunnel to access it on a local PC.

Submit a vscode-server job to a computing node

Create the following file:

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Send job to queue using sbatch command on the login node of Ares

sbatch vscode-run.slurm

Wait until your job enters the running state.

To check the status of the submitted job using using squeue command

squeue -j <JobID>

or all jobs of the user

squeue -u $USER

which lists all  current user jobs submitted to the queue ($USER - is an environment variable).

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• PD - PENDING - Job is awaiting resource allocation.
• R - RUNNING - Job currently has an allocation and is running.
• CF - CONFIGURING  - Job has been allocated resources, but are is waiting for them to become ready for use (e.g. booting). On Ares Ares CF state state could last for up to 8 minutes in case when nodes that have been in power save mode.
• CG - COMPLETING  - Job is in the process of completing. Some processes on some nodes may still be active.

Make a tunnel

When the job will startstarts, it will create a file named code-server-log-<jobID>.txt  in the folder from which the sbatch command was called. Go to this directory and use cat  to see the contents of VSCode log file:

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    Copy/Paste this in your local terminal to ssh tunnel with remote
    -----------------------------------------------------------------
    ssh -o ServerAliveInterval=300 -N -L 9633:172.22.17.186:9633 plguser@ares.cyfronet.pl
    -----------------------------------------------------------------
    Then use Web UI link located at the end of the log in your web browser:

*
* Visual Studio Code Server
*
* By using the software, you agree to
* the Visual Studio Code Server License Terms (https://aka.ms/vscode-server-license) and
* the Microsoft Privacy Statement (https://privacy.microsoft.com/en-US/privacystatement).
*
Web UI available at http://localhost:9633?tkn=ee8e3c6e34ad22ea267a9532635cabe8d1b5fbc59b8705e91737a6129a866b5b

In At the top, we can see a command prepared for you to run in your local terminal.

Copy it and execute it in your local terminal:

ssh -o ServerAliveInterval=300 -N -L 9633:172.22.17.186:9633 plguser@ares.cyfronet.pl

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To preserve the VSCode server data and VSCode environment, use the option --server-data-dir pointing at some directory of your choice. The location should be the same each time to save configuration. In this example, we have used  $SCRATCH/vscodedata path as the storage location.

Stop job

if you wish to to end your sbatch, use scancel <JOBID> command, where JOBID is your tunnel JOBID you can look it up with hpc-jobs or squeue -u $USER commands.

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To check information about finished and historic jobs use hpc-jobs-history command. For example with the option "-d 30"  that command shows all user's jobs from the last 30 days. More info in hpc-jobs-history -h. 

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To use on Athena supercomputer, you need to change --partition  to plgrid-gpu-a100 and name of the module to load: VSCode/1.85.0.

Skrypt z tymi zmianami znajduje się poniżejThe script with those modifications can be found below:

#!/bin/bash
#SBATCH --partition plgrid-gpu-a100
#SBATCH --nodes 1
#SBATCH --ntasks-per-node 6
#SBATCH --time 0:30:00
#SBATCH --job-name code-server
#SBATCH --output code-server-log-%J.txt

module load VSCode/1.85.0

mkdir -p $SCRATCH/vscodedata

## start an rserver instance
start-vscode-web --server-data-dir $SCRATCH/vscodedata

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