Linux Desktop Visualization (Viz)

The Viz nodes provide a full graphical Linux desktop that you reach through your web browser using FastX. Use it for GUI applications, visualization, and previewing results, or as a desktop gateway to the clusters. See the Viz node hardware for specifications.

Connect to the VPN first

Like the other CRCD resources, Viz is reachable only from the University network. From off campus, connect to the GlobalProtect VPN first (see Step 1).

Step 1. Log in to FastX

Point your browser to https://viz.crc.pitt.edu and sign in with your Pitt credentials. Enter your Pitt username (1) in all lowercase and your Pitt password (2), then click SSH Login (3).

FastX SSH login page with the Username field, Password field, and SSH Login button

Use all lowercase for your username

If you are unexpectedly prompted for a second password, you most likely entered your username with capital letters. Reload the page and sign in again using your Pitt username in all lowercase.

Step 2. Launch a desktop session

After logging in you land on the My Sessions page. The Applications panel on the left lists the available desktops and terminals — mate, xfce, and xterm. Click mate (a good default desktop) to start a new session.

FastX My Sessions page showing the Applications list (mate, xfce, xterm) with mate selected

Step 3. Choose how to connect

FastX asks how you want to open the session. Choose Browser Client to run the desktop in a new browser tab with nothing to install; the Open in New Tab option is selected so the desktop opens in its own tab. The Desktop Client is an alternative that generally handles copy and paste better — download it with the link on this screen if you prefer it.

FastX prompt asking how to connect to the session, with Browser Client and Desktop Client options

Step 4. Use the desktop

Your MATE desktop opens in the browser. Use it like any Linux desktop: the Applications, Places, and System menus are in the top-left, and the desktop icons give you your home folder, Computer, and Trash.

MATE desktop session running in the FastX browser client

If the desktop does not fill the window — as below, where the StarNet background shows around a smaller desktop — use the toolbar on the right edge of the session to fit or resize it.

MATE desktop shown smaller than the browser window, with the StarNet watermark border visible

Step 5. Run an application

Open a terminal from the desktop by clicking the terminal icon in the top menu bar (1), which starts Mate Terminal (2). From there you can load software with the module system and launch it. For example, to start MATLAB:

module load matlab
matlab

MATE desktop with a terminal running 'module load matlab' and MATLAB R2025a open

Step 6. Reconnect or end your session

Your session keeps running on the Viz node even if you close the browser tab, navigate away, or lose your network connection — you are only disconnected, not logged out. To pick up where you left off, return to https://viz.crc.pitt.edu: any running session appears under Connected Sessions on the My Sessions page. Click its thumbnail to reconnect exactly where you left it — handy for long-running GUI work you come back to over several sittings.

FastX My Sessions page showing a running 'mate' session under Connected Sessions

Reconnect or terminate from My Sessions

From the My Sessions page you can click a Connected Session to reconnect, or terminate it there without reopening it. Closing the browser tab only disconnects — the session (and its resource use) keeps running until you log out or terminate it.

Because a disconnected session keeps consuming resources, log out from inside the desktop when you are truly finished. Click through the sequence below.

LibreOffice and a terminal open on the MATE desktop before logging out

Save your work and close any open applications — here, LibreOffice, launched with module load libreoffice then soffice.

The MATE System menu open with 'Log Out gnowmik…' highlighted

From the desktop menu bar, open System and choose Log Out gnowmik…. (The Shut Down… entry just below does the same thing — it ends your session, not the shared Viz node.)

MATE 'Log out of this system now?' dialog with Switch User, Cancel, and Log Out buttons

Click Log Out to confirm — or just wait for the short countdown to log you out automatically.

FastX 'Client Disconnected — the session exited normally' message with a Home button

FastX confirms the session exited normally and its resources are freed. Click Home to return to My Sessions.

Back on the My Sessions page, No Sessions Running confirms the session has fully ended and its resources are freed — compare with Connected Sessions above, where it was still available to reconnect.

FastX My Sessions page showing No Sessions Running

Definitions

  • FastX -- the StarNet remote-desktop software that streams a Linux graphical desktop to your browser or to a local desktop client.
  • MATE / XFCE -- lightweight Linux desktop environments; either works for a Viz session, and MATE is a good default.
  • session -- a running desktop or application on a Viz node; sessions persist until you terminate them.