SLURM VNC interactive jobs
From UABgrid Documentation
This page contains outdated information. While the method outlined here should still work, the easiest way to access a VNC-like desktop on Cheaha is to use the Open OnDemand web portal to create and access an Interactive HPC Desktop job through your web browser.
Using VNC session
Please refer to our VNC setup guide to start a VNC session with Cheaha login node. After getting your VNC desktop, you can get a compute node resource using the sinteractive command. A sinteractive session launched through VNC won't get terminated even if your SSH or VNC window is closed. Of course, it will get terminated after specified run-time is reached.
After you login to Cheaha the command-line interface that you see is running on the login node. Most of your light interactive prep-work to submit a compute job to the scheduler can be carried out on this login node. If you have a heavier workload to prepare for a batch job (eg. compiling code or other manipulations of data) or your compute application requires interactive control, you should request a dedicated interactive node for this work.
Interactive resources are requested by submitting an "interactive" job to the scheduler. Interactive jobs will provide you a command line on a compute resource that you can use just like you would the command line on the login node. The difference is that the scheduler has dedicated the requested resources to your job and you can run your interactive commands without having to worry about impacting other users on the login node.
Interactive jobs are requested with the sinteractive command (please use your correct email address in place of the $USER@uab.edu string if you do not have an @uab.edu email address):
sinteractive --nodes=1 --time=120 --mail-user=$USER@uab.edu --mail-type=begin,end,fail
This command requests 1 node (24 cores) with entire allocation of RAM on the node for 120 minutes (2 hours). The command will wait until the resource is reserved by the scheduler and send you an email when the resource is available. The email alert can be useful during periods of heavy cluster demand when interactive resources reservations may have significant wait times.