HiPerGator 2.0 documentation

Full Xpra Documentation

Xpra Homepage: https://xpra.org/
Xpra Basic Usage: https://xpra.org/trac/wiki/Usage
Xpra Advanced Usage: http://xpra.org/manual.html

Step 1: Client Installation

Xpra client installation depends on the operating system running on your local machine and may require assistance of a system administrator if you do not have the authority to install new software. Once Xpra is installed on your client computer feel free to skip this step. Click on the link specific to the operating system running on your local computer.

Step 2: Start a GUI session on HiPerGator

The simplest way to start a GUI application session on HiPerGator is to use the pre-made launcher script available for approved commonly used applications.

Launch a pre-approved application

To launch a pre-approved application for which we prepared a launcher script only two steps are needed: Load the application environment module

module load application

Launch the application

launch_xpra_application

See an example on the RSTudio Help Page.

Launch any application

Use a sample job script as the base of your gui session job. Sample job scripts can be found in the '$HPC_GUI_JOB' directory once the 'gui' environment module is loaded.

Within the job script use the xpra_start wrapper to launch the application within the shell section of the job script.

module load application
xpra_start application

List Xpra Sessions

Once you submit a job wait for it to start. Check the job status with 'squeue -u $USER'. When the job starts list the available xpra sessions using xpra_list_sessions command in the gui module. This command will refresh the Xpra session list and provide a convenient list of live Xpra sessions as well as client commands that can be copied and pasted into a terminal on the client machine.

Example

$ module add gui
$ xpra_list_sessions

Output:

Refreshing the session list for jdoe to remove stale sessions

List of active Xpra sessions for jdoe:

Session: i111a-s222.rc.ufl.edu:3713
    Job ID: 123456, Name: RStudio
    Client command:
         xpra attach ssh:jdoe@i111a-s222.rc.ufl.edu:3713
        or (downloaded script):
         ./xpra attach ssh:jdoe@i111a-s222.rc.ufl.edu:3713

See the respective application pages for details and sample job scripts.

Step 3: Connect to Xpra Session from the client computer

Connecting from outside of UF campus via VPN

The nodes in SLURM gui partition are accessible only within the UF campus network. If you are working off campus, you will need to use the VPN to connect to the UF campus network using AnyConnect VPN or similar software. Please see: https://vpn.ufl.edu for additional information.

Linux

Xpra is typically automatically added to your path during installation, so you can connect to your running xpra instance using the following syntax where $USERNAME is your UF GatorLink user-name, $SERVERNAME is the server where your application is running inside xpra, and $PORT is the X11 port you assigned when you started your application.

xpra attach ssh:$USERNAME@$SERVERNAME:$PORT

As an example:

testuser@jr-physics:~$ xpra attach ssh:testuser@i21a-s3.rc.ufl.edu:143 --desktop-scaling=on --dpi=96

The xpra_list_sessions command presents a ready-to-use connection command, but you'll have to add the desktop scaling or dpi arguments manually.

Please note that if you close the application window using the close button in the top right (or left) corner, this will exit your application and terminate your SLURM gui session. If you want to simply detach the session and come back later, please follow the detaching xpra session instructions below

MAC OS

Navigate to the folder that contains the Xpra executable:

cd /Applications/Xpra.app/Contents/MacOS

Alternatively, call the xpra shell script you downloaded during client software installation.

Use the client command provided by 'xpra_list_sessions' to connect while adding any local options you need to improve the viewing experience like

Desktop scaling: --desktop-scaling=on
Resolution, dpi (dots per inch): --dpi=96

Example:

./Xpra attach ssh:test-user@i21a-s3.rc.ufl.edu:143 --desktop-scaling=on --dpi=96

or with the wrapper script in place

xpra attach ssh:test-user@i21a-s3.rc.ufl.edu:143 --desktop-scaling=on --dpi=96

Once the GUI application windows is displayed on your local computer if you close the window using the close button both the application and SLURM gui session will close. If you want to simply detach the session and come back later click on the terminal window where you ran the client command and use the 'Ctrl+c' key combination to detach the session.

Microsoft Windows

Navigate to the install location of xpra (normally C:\Program Files (x86)\Xpra\).

In MobaXterm

cd "/drives/c/Program\ Files\ \(x86\)/Xpra/"