GUI Programs

Here you will find the information necessary to configure and run graphical user interface (GUI) applications on HiPerGator. The process is not complicated, but running a GUI on a remote server and displaying the windows on your local client computer with a sufficiently responsive interface is not as easy as simply running the application locally. To accomplish this task we use Xpra software - an open-source multi-platform persistent remote display server and client for forwarding application and desktop screens. Full information on Xpra can be found in its basic usage documentation and the Xpra manual. Below we show the parts of Xpra documentation relevant to running GUI Programs on HiPerGator.

Install Xpra Software on the Client Computer

Since Xpra is required on both ends of the connection you will have to have it installed on your local computer. 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. Installation instructions are specific to the operating system running on your local computer:

• Windows
• MacOS X
• Linux

Start a GUI Session on HiPerGator

Note

The launch_gui_session script described in the sections below takes a number of arguments allowing specification of the number of cpu cores, memory, time limit, and more. Please run

module load gui
launch_gui_session -h

to see all available arguments.

Single command, no job script

There are two classes of applications that can be started with just one command from the gui environment module and do not require you to provide a job script.

Preset applications

Expand

Expand this section to view instructions for starting preset applications without a job script.

To list applications presets load the gui module and run launch_gui_session -l

module load gui
launch_gui_session -l

To launch a pre-approved application:

• Load the gui module if not already loaded:

module load gui

• Launch the application:

launch_<application>_gui

For example:

launch_mzmine_gui

or:

launch_rstudio_gui

See a full example on the RSTudio Help Page. For MATLAB options, please see the MATLAB Help Page.

Simple applications

Expand

Expand this section to view instructions for starting a simple application without a job script.

If you want to run a simple application in which either the environment module name matches the name of the program you want to run or you've already loaded the environment module and know the name of the executable then the process is about as simple as launching a preset application

Load the application environment module if its name is different from the executable name

module load <application>/<version>

Launch the executable in a GUI session:

module load gui
launch_gui_session -e <application>

For example:

launch_gui_session -e molden

Note

if the name of the application and its environment module name are different you can use the '--module <module_name>' argument to load a specific module.

For example:

launch_gui_session -e beauti --module beast/2.4.3

or

launch_gui_session -e gv --module gaussian

Provided job script

If you need to pass custom arguments to the application, load pre-requisite environment modules or run additional commands, you can provide a simple script (linux format text file) with the required commands as an argument to launch_gui_session.

Make sure to prepend the command that starts the program with xpra_start. For example, a following job script named my_molden.sh will use the molden/5.0 environment module and start molden with a particular model file:

module load molden/5.0
xpra_start 'molden /ufrc/data/tests/molden/boc-iso-1t.gjf'

Now, to launch molden with the above script run:

launch_gui_session -e molden -f my_molden.sh

Manual launch

If you prefer to talk directly to SLURM you can write a full job script complete with resource requirements, job name, output file, etc in the #SBATCH section and submit the script to SLURM manually.

Make sure you use the gui partition:

#SBATCH --partition=gui

and wrap your command with xpra_start as shown above.

You can use a job script for one of the application presets found in the '$HPC_GUI_JOB' directory once the 'gui' environment module is loaded as the base of your own job script.

List GUI Sessions

If you performed a manual launch or used the '-w' argument to the automated launcher command you'll have to manually check on your gui job. Check the job status with 'squeue -u $USER'. When the job starts you have to 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 load gui
$ xpra_list_sessions 

Output:

Refreshing Xpra session list for jdoe. This could take a while.....

List of active Xpra sessions for jdoe:

Session: i21a-s33.rc.ufl.edu:9626 for RStudio job 2852284
    Client command:
         xpra attach ssh:jdoe@i21a-s33.rc.ufl.edu:9626

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

Connect From a Client Computer

Servers in the 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.

Connecting from Linux

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Expand this section to view connection instructions for Linux/Unix.

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 with --desktop-scaling=on or resolution, dpi (dots per inch) with --dpi=96

Command

$USERNAME is your UF GatorLink username, $SERVERNAME is the GUI server address, and $PORT is the X11 port.

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

Example: jdoe@local_computer:~$ xpra attach ssh:testuser@i21a-s33.rc.ufl.edu:12345 --desktop-scaling=on --dpi=96

Note

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. Use 'Ctrl+c' key combination in the terminal windows where you ran the xpra attach command to disconnect the session if you plan to reconnect later.

Connecting from MacOS X

Expand

Expand this section to view connection instructions for MacOS X.

Note: This is done ON YOUR PERSONAL COMPUTER since you will be connecting from it to HiPerGator. Do not run this command on HiPerGator.

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 with --desktop-scaling=on or resolution, dpi (dots per inch) with --dpi=96

Example:

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 the SLURM gui session will close. If you want to detach from the session (leaving it running) and return later, click on the terminal window where you ran the client command and use the 'Ctrl+c' key combination to detach from the session.

Note: If the xpra script was not installed by the .pkg installer or manually as noted on the client software installation page, you will need to change into the Xpra installation directory before running Xpra executable.

cd /Applications/Xpra.app/Contents/MacOS
xpra attach ssh:test-user@i21a-s3.rc.ufl.edu:143 --desktop-scaling=on --dpi=96

Connecting from Microsoft Windows

Expand

Expand this section to view instructions for logging in with Microsoft Windows.

Note: This is done ON YOUR PERSONAL COMPUTER since you will be connecting from it to HiPerGator. Do not run this command on HiPerGator.

Assuming the xpra shell script was downloaded and installed as on the client software installation page. You can open a new terminal window and paste the xpra connect command:

Example

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 the 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.

Note: If the xpra script was not installed, you will need to navigate to the install location of xpra (normally C:\Program Files (x86)\Xpra\) .

In MobaXterm

cd "/drives/c/Program\ Files\ \(x86\)/Xpra/"
xpra attach ssh:test-user@i21a-s3.rc.ufl.edu:143 --desktop-scaling=on --dpi=96

Special cases (GUI scaling, font issues, etc)

See the Special Cases page for GUI Programs if you run a program or a local system that requires special care compared to the normal usage. Some examples of special cases include desktop scaling and DPI issues.