Interactive Desktop

Opening Interactive Desktop Form

  • The first step is to select the Interactive apps and then click the Desktop(XFCE) in the Open OnDemand dashboard.

  • Then you will see a form which needs to be filled to launch the interactive desktop on the compute nodes.

ood-desktopform.png

Partition

  • Partitions are work queues that has computational nodes in it to run the jobs. The partitions available in Discovery are interactive,normal, gpu, backfill, class, epscor, iiplab, cfdlab, so on.

  • However, you will see only the list of authorized partitions available for your Discovery account and hence, you won’t see the partitions which you don’t have authorization in the select dropdown.

  • Select one of the partitions where you want to submit your job. Refer to the page → Partitions in Discovery to select the ideal partition for your job.

  • By Default, partition is set to interactive.

Walltime(Hours)

  • Sets the Walltime for your job. The job gets killed if the Walltime you set gets elapsed.

    Parameter #Hours

    Min Limit

    1 hour

    Max Limit

    24 hours

    Default

    1 hour

CPUs(Threads)

  • Sets the Number of CPUs(Threads) for the job. The below table shows the maximum limit for CPU threads for each partition. The default and minimum value is 1 CPU thread.

    Partition Max Limit

    interactive

    16

    normal

    44

    gpu

    28

    epscor

    124

    iiplab

    52

    cfdlab

    52

    class

    60

Memory (GB/Gigabytes)

  • Sets the memory for the job in terms of GB. The memory you select is available to all assigned threads for the job. The below table shows the maximum memory limit for each partition which can be requested for the job. The default and minimum value is 1 GB.

Partition Max Memory Limit(GB)

interactive

64

normal

240

gpu

50

epscor

3000

iiplab

175

cfdlab

175

class

490

GPUs

  • To enable the GPU selection, you need to choose one of the following partitions: interactive, class, gpu, epscor, iiplab, cfdlab. Only these partitions have GPUs and if you select any of the partitions, you can see the GPUs dropdown enabled.

    Parameter #GPU

    Min Limit

    0

    Max Limit

    2

Partition normal don’t have GPUs.

Email Address

  • If you want to get notified via email when the job starts/fails/ends, enter the email address associated with the Discovery account.

  • You can leave the text field blank if you don’t want job notifications.

Launching the Interactive Session

  • Once all the form fields are set, you can click the Launch button. The interactive session will be launched and the below output is shown.

ood-desktop-launch1.png
  • The above output shows that the interactive Desktop session has been launched successfully. You will see the Launch Desktop(XFCE) only if the resources you have requested becomes available. Else, you might need to wait for some more minutes for the resources allocation and then the Launch Desktop(XFCE) button appears.

  • You can also set the Compression and Image Quality for Interactive Desktop by using the slider. After setting the values, click the Launch Desktop(XFCE) button.

The interactive session won’t be launched if you try to submit your job to the partition that you don’t have access to. You will get the following error message → Batch job submission failed: User’s group not permitted to use this partition. Also, the page gets reloaded and you need to select the value for the form fields again since the form gets reset.

Opening Interactive Desktop

  • On clicking the Interactive Desktop(XFCE) button, the interactive desktop opens in a new tab through a VNC session.

  • You are provided with four different workspaces which is displayed in the top right corner of the window and you can use it.

ood-desktop-output.png
  • At the bottom of the screen, you will see different options like Terminal Emulator, File Manager, Application Finder, Web Browser, Minimize windows which you can make use of it.

Opening applications

  • Click the Applications tab in the top left of the screen and you will see the list of available applications.

Output:

ood-desktop-apps.png

Killing the interactive session

  • Click the Applications tab and then select the Logout option.

  • Then, you will get a pop-up to confirm.

ood-desktop-logout.png
  • On confirmation, you will be disconnected and the interactive session gets deleted. You will see a similar output like below:

ood-desktop-disconnect.png

Alternate way

  • Another way to delete the session is to go to the My Interactive sessions tab and select the Delete button of the current interactive session.

ood-desktop-delete.png

Whenever you are done with the work, it’s always recommended to kill/delete the interactive session running on the compute nodes and free the resources.