Linux Desktop Visualization (Viz)¶
The Viz nodes provide a full graphical Linux desktop, accessed through FastX. You can connect in three ways: straight from your web browser with nothing to install, or with the FastX desktop client on macOS or Windows — a small app that generally handles copy and paste better and lets you save connection profiles you can reopen with a double-click. Use it for GUI (Graphical User Interface) applications, visualization, and previewing results, or as a desktop gateway to the clusters. Pick your method in the tabs below. See the Viz node hardware for specifications.
Connect to the VPN (Virtual Private Network — required to reach the clusters) first
Like the other CRCD resources, Viz is reachable only from the University network. From off campus, connect to the GlobalProtect VPN (Virtual Private Network — required to reach the clusters) first (see Step 1).
The browser client runs the desktop in a new tab with nothing to install — the quickest way to get a Viz session.
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 (Secure Shell — protocol for connecting to a login node) Login (3).
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.
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 — see the macOS client or Windows client tab above to set it up.
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.
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.
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
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 (Graphical User Interface) work you come back to over several sittings.
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.
1. Save work — save your work and close any open applications; here, LibreOffice,
launched with module load libreoffice then soffice.
2. Log out — 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.)
3. Confirm — click Log Out to confirm, or just wait for the short countdown to log you out automatically.
4. Disconnected — 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.
The desktop client is a small app you install on your Mac. It generally handles copy and paste better than the browser and lets you save connection profiles you can reopen with a double-click.
Step 1. Download and install FastX
Download the macOS FastX client from https://www.starnet.com/download-fastx-client/ —
click MacOS Client — and open the .dmg file. In the window that opens, drag the
FastX5 icon onto the Applications folder shortcut to install it.
The first time you launch FastX, macOS warns that it is an app downloaded from the Internet. Click Open to continue. (You only need to confirm this once.) Launch FastX from your Applications folder — not from the mounted disk image.
If macOS blocks the app
If macOS refuses to open the app instead of offering an Open button, right-click (or Control-click) FastX5 in your Applications folder and choose Open from the menu, then confirm.
Step 2. Add a connection
When FastX opens you land on the Connections tab. Click the + button (1) to create a new connection to the Viz node, then fill in the Edit Connection dialog (2) with the settings below and click OK.
| Field | Value |
|---|---|
| Protocol | https |
| Host | viz.crc.pitt.edu |
| User | your Pitt username, in all lowercase |
| Port | 443 |
| Uri | leave blank |
| Auth | SSH (Secure Shell — protocol for connecting to a login node) |
| Name | viz (or any label you like) |
Under Advanced, check Ignore SSL errors. Leave Route all Connections Through Gateway and Disable URL Open unchecked.
| Add the viz connection | |
|---|---|
1  |
2  |
Use all lowercase for your username
Enter your Pitt username in all lowercase. Capital letters can cause FastX to unexpectedly prompt you for a second password.
Step 3. Connect and log in
Your saved viz connection now appears on the Connections tab. Double-click it to connect (1). When prompted, enter your Pitt username in all lowercase and your Pitt password, then click Continue (2). (On the connection tile, the pencil icon edits the connection, the heart marks it as a favorite, and the ✕ removes it.)
| Connect and log in | |
|---|---|
1  |
2  |
Step 4. Launch a desktop session
After logging in you land on the My Sessions page for the viz connection. Click the + button to start a new session.
The Applications picker lists the available desktops and terminals — mate, xfce, and xterm, plus VirtualGL variants for hardware-accelerated graphics. Select mate (a good default desktop) and click OK.
VirtualGL variants
The mate - VirtualGL and xfce - VirtualGL entries run the desktop with VirtualGL for hardware-accelerated OpenGL. Choose one of these if your application needs 3D graphics.
Step 5. Use the desktop
Your MATE desktop opens in its own window. 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.
If you step away, the session may lock itself after a period of inactivity. When it does, MATE shows a lock screen — type your Pitt password and click Unlock to resume.
Step 6. Open a terminal and run software
To open a terminal, right-click anywhere on the desktop background and choose Open in Terminal.
A terminal opens. From there you can load software with the module system and launch it — for example:
module load matlab
matlab
Step 7. Reconnect or end your session
Your session keeps running on the Viz node even if you close the FastX window or lose your network connection — you are only disconnected, not logged out. To pick up where you left off, reopen FastX, connect to viz again, and click the running session's ▶ on the My Sessions page to reconnect exactly where you left it.
Log out when you are truly finished
Because a disconnected session keeps consuming resources, log out from inside the desktop when you are done: from the desktop menu bar open System and choose Log Out, then confirm. Closing the FastX window only disconnects — the session (and its resource use) keeps running until you log out or terminate it.
The desktop client is a small app you install on your Windows PC. It generally handles copy and paste better than the browser and lets you save connection profiles you can reopen with a double-click.
Step 1. Download FastX
Open https://www.starnet.com/download-fastx-client/ in your browser and click Windows Client (exe) to download the installer. (If you do not have administrator rights on your PC, use the Windows Non-Admin Client link instead.)
Step 2. Run the installer
Double-click the downloaded .exe and work through the setup wizard, following the panels
below in order:
- User Account Control asks whether to allow the app to make changes (publisher StarNet Communications Corp.) — click Yes.
- On the welcome screen, click Next.
- Read the license agreement, check I accept the terms in the License Agreement, and click Next.
- Leave the default install location (and the desktop-shortcut option, if you want one) and click Next.
- Click Install to begin.
- When the wizard finishes, click Finish to close it.
| Install the FastX client | |
|---|---|
1  |
2  |
3  |
4  |
5  |
6  |
Step 3. Launch FastX and add a connection
Open the Start menu (1) and click FastX 5 (2) to launch the client. (It also appears on the desktop if you kept the shortcut, or you can search for "FastX".)
FastX opens on the Connections tab. Click the + button (1) to create a new connection to the Viz node, then fill in the Edit Connection dialog (2) with the settings below and click OK.
| Field | Value |
|---|---|
| Protocol | https |
| Host | viz.crc.pitt.edu |
| User | your Pitt username, in all lowercase |
| Port | 443 |
| Uri | leave blank |
| Auth | SSH (Secure Shell — protocol for connecting to a login node) |
| Name | viz (or any label you like) |
Under Advanced, check Ignore SSL errors. Leave Route all Connections Through Gateway and Disable URL Open unchecked.
| Add the viz connection | |
|---|---|
1  |
2  |
Use all lowercase for your username
Enter your Pitt username in all lowercase. Capital letters can cause FastX to unexpectedly prompt you for a second password.
Step 4. Connect and log in
Your saved viz connection now appears on the Connections tab. Double-click it to connect (1). When prompted, enter your Pitt username in all lowercase and your Pitt password, then click Continue (2). (On the connection tile, the pencil icon edits the connection, the heart marks it as a favorite, and the ✕ removes it.)
| Connect and log in | |
|---|---|
1  |
2  |
Step 5. Launch or reconnect to a desktop session
After logging in you land on the My Sessions page. Click the + button to start a new session. Any session you already have appears here as a tile — click its ▶ (play) button to reconnect to it exactly where you left off.
If you reconnect to a session that locked itself while you were away, MATE asks for your password. Type your Pitt password and click Unlock.
Your MATE desktop opens in its own window. 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.
Step 6. Launch another desktop and open a terminal
To start a different desktop, click + on the My Sessions page. The Applications picker lists the available desktops and terminals — mate, xfce, and xterm, plus VirtualGL variants for hardware-accelerated graphics. Select one — here xfce — and click OK.
VirtualGL variants
The mate - VirtualGL and xfce - VirtualGL entries run the desktop with VirtualGL for hardware-accelerated OpenGL. Choose one of these if your application needs 3D graphics.
In the XFCE desktop, right-click anywhere on the background and choose Open Terminal Here.
A terminal opens. From there you can load software with the module system and launch it — for example:
module load matlab
matlab
Step 7. Reconnect or end your session
Your session keeps running on the Viz node even if you close the FastX window or lose your network connection — you are only disconnected, not logged out. To pick up where you left off, reopen FastX, connect to viz again, and click the running session's ▶ on the My Sessions page to reconnect exactly where you left it.
Log out when you are truly finished
Because a disconnected session keeps consuming resources, log out from inside the desktop when you are done: from the desktop menu bar open System and choose Log Out, then confirm. Closing the FastX window only disconnects — the session (and its resource use) keeps running until you log out or terminate it.
Definitions¶
- FastX — the StarNet remote-desktop software that streams a Linux graphical desktop to your browser or to a local desktop client.
- desktop client — the FastX app installed on your Mac or PC; an alternative to the browser client that handles copy and paste better and stores saved connections.
- MATE / XFCE — lightweight Linux desktop environments; either works for a Viz session, and MATE is a good default.
- VirtualGL — a toolkit that gives a remote Linux session hardware-accelerated OpenGL for 3D graphics.
- session — a running desktop or application on a Viz node; sessions persist until you terminate them.