Virtual Desktop

On UCloud it is possible to run web-based desktop applications. These software applications are installed in a virtual desktop environment (VDE) based on a Linux distributions, namely CentOS or Ubuntu. Examples of software applications with a graphical user interface (GUI) deployed in a VDE include: ANSYS, COMSOL, MATLAB, and KNIME.

Note

In some of the VDE apps the software GUI is launched at the startup, while closing the GUI also terminates the job.

In order to launch a VDE app, the user should follow the same procedure depicted in the previous section for interactive apps. In this case, however, by clicking on

a remote desktop is opened inside a pop-up window, which can be arbitrarily resized.

Additional features of VDE apps are summarized below.

Web browsers

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Direct access to internet is provided by the Chromium and Firefox web browsers.

Remote filesystem

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The remote filesystem of the application container can be browsed via the Linux filemanager. In case data folders are mounted from UCloud, they will appear within the /work directory, which is the default working tree of the application container.

Important

Only new files and folders created inside the default working tree will be saved after job completion.

Terminal window

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Access to a shell window is provided by the Terminal application on the desktop. The startup directory in this case is always /work. The default user inside the application container is ucloud, which has also superuser account privileges. Therefore, full read, write, and execute permissions are enabled using sudo in front of any command, without entering an administrator password. Before installing a new software, it is recommended to update the system libraries. For this purpose, run the command

$ sudo yum update

for a CentOS-based app, and

$ sudo apt-get update

in case of an Ubuntu-based app.

Display resolution

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The desktop resolution can be changed using the Display application installed in the operative system.

Custom display resolutions can be added from the terminal window. For example, for a screen of 2560x1440 pixels at 60 Hz, first run the command

$ cvt 2560 1440 60

Tip

# 2560x1440 59.96 Hz (CVT 3.69M9) hsync: 89.52 kHz; pclk: 312.25 MHz

Modeline "2560x1440_60.00" 312.25 2560 2752 3024 3488 1440 1443 1448 1493 -hsync +vsync

then, create the new display mode using the second line in the output, as shown below:

$ xrandr --newmode "2560x1440_60.00"  312.25  2560 2752 3024 3488  1440 1443 1448 1493 -hsync +vsync

and

$ xrandr --addmode VNC-0 2560x1440_60.00

The new resolution can be selected directly from the Display application or via command line:

$ xrandr --output VNC-0 --mode 2560x1440_60.00