ICS@PSU: Institute for CyberScience

Submitting an Interactive Job on ACI-B

Why would I need to run an interactive job on the batch system?

  • You need more RAM or CPUs than are available on ACI-I
  • You want dedicated resources for an interactive job
  • You want to be able to interact with your job as it runs – such as starting a 2nd task based on preliminary results within the same job

What are some downsides to running an interactive job on the batch system?

  • Must wait on the queue before it starts
  • Job won’t stop when your task stops
  • The graphics are slow to respond
  • There are no local GPUs on basic/standard/highMem nodes


  1. Log onto ACI-B
    1. Be sure to use secure X-window forwarding if you wish to use graphics
      1. Use the –Y flag with the ssh command

        [abc123@comp-ic-0023 ~]$ ssh -Y abc123@aci-b.aci.ics.psu.edu 
      2. We suggest using MobaXterm on windows to connect with for graphics. You can download this: https://mobaxterm.mobatek.net/ and be sure that the X-server is enabled
      3. You can use Putty, but you will have to have an x-server installed – most x-servers have
      4. Note that you will still need to use the –Y flag if you ssh from an Exceed onDemand session on ACI-I
  1. Submit an interactive job
    1. Use the –I (as in Iowa) flag for an interactive job
    2. Use all of the other PBS directives that you would for a batch job to request walltime, processors, memory
    3. Use the –X flag for x-window forwarding if you want access to a GUI window
    4. Example:

      qsub –I -X -A open -l walltime=1:00:00 -l nodes=1:ppn=2 -l pmem=8gb
  1. Wait in that terminal session for your job to start
    1. Example text on the screen after submission to the open queue:
      Job will run under the ‘open’ account, as requested.
      qsub: waiting for job 42.torque01.util.production.int.aci.ics.psu.edu to start
    2. Example text on the screen after submission to an allocation:
      Job options fit within the PI reservation.
      qsub: waiting for job 42.torque01.util.production.int.aci.ics.psu.edu to start
    3. You may want to log in with a second terminal to be able to run showq or qstat
    4. When your job is ready you will get a message:
      qsub: job 42.torque01.util.production.int.aci.ics.psu.edu ready
    5. Then you will get a prompt on the compute node (or master compute node for multi-node jobs):
      [abc123@comp-bc-0208 ~]$
  1. Use this as you would any other terminal session but on the resources you requested
    1. Load your modules, go to the correct location and run your code
    2. You can test X-window forwarding with the command xterm
  2. End your job when your task is done
    1. Use the command exit
      1. If you do not do this, the job will stay running until killed by the system based on your requested wall-time, charging you for all hours
    2. You will get a logout message and then be placed back on the command prompt:
      [abc123@comp-bc-0208 ~]$ exit

      qsub: job 42.torque01.util.production.int.aci.ics.psu.edu completed
      [abc123@aci-lgn-006 ~]$

Penn State Institute for CyberScience

Help us build the future. Contact ICS at Penn State.

  • email: ics@psu.edu
  • phone: ICS-ACI Support (i-ASK Center): 814-865-4275 | General Inquiries: 814-867-1467

April 2018

  • No events sheduled for April.