Remote Desktop on Qarnot Cloud - Documentation

Introduction

VNC is a desktop-sharing system that allows to remotely control another computer. With this system, a user can access a remote desktop and use applications as if they were using a normal computer. It can be used to visualize and manipulate possibly large computation results on a powerful computer.

The system uses multiple components such as a VNC server and a VNC Client. We use TigerVNC for the server, and noVNC (with a webSockify proxy) for the client, both are open-source projects. noVNC allows the user to access the remote desktop without the need to install any software on their computer, only with a modern web browser (i.e. Firefox, Chrome…).  The system also comes with a specific software installed, like Paraview or Ansys Fluent.

This guide will walk you through running and accessing a remote Desktop with an installation of paraview on the Qarnot platform.

Versions

If you are interested in another version, please email us at support@qarnot.com

Prerequisites

Before trying a test case, please ensure that the following prerequisites have been met.

• Create a Qarnot account: register
• Retrieve your authentication token
• Install one of Qarnot’s SDK (Python)(Node.js)(C#)(Command Line)
• Have a recent web browser (Firefox, Chrome, ...)
• Have a SSH public key (you can create one by following this tutorial)

Test case

We propose to use a  motorbike file example, that is part of an OpenFoam tutorial, to test the remote desktop on a real case. This file can be opened in Paraview.

Launching the case

Here is an example on how to start a remote desktop on the Qarnot platform and open the test case in Paraview. It assumes that the test case is inside a input/ directory in your working directory.

To launch the remote desktop on Qarnot, copy this code in a Python script in your working directory. Be sure you have :

• copied your authentication token in the script (instead of <<<MY_SECRET_TOKEN>>>)
• copied your public SSH key in the script (instead of <<<MY_SSH_PUBLIC_KEY>>>)

Results

Once the python script has been launched, it will wait for the task to be executing on the Qarnot infrastructure before opening the connection to the remote desktop. 

When the tasq is executing, its information page on the Tasq website should look like this :

You can then access to the URL localhost:6080/vnc.html in your web browser and connect to the remote desktop by simply clicking on the connect button as follow.

Then, you can launch Paraview by using the launcher on the desktop and open the /job/input/motorBike.obj file to view our example.

When the connection is established, the user can change the quality and compression settings to improve the frame-rate of the video by opening the settings menu on the left side of the screen. We recommend to use a medium quality for a smoother experience. 

Wrapping up

That’s it! If you have any questions, please contact qlab@qarnot.com and we will help you with pleasure!