[OOD-users] VDI

Fri Mar 23 14:41:18 EDT 2018

Susan,

The OSC use of a “Quick” cluster is likely unnecessary for SLURM sites.  One reason we have a separate cluster in Torque/Moab is to have a shorter scheduling interval which we couldn’t support on the larger clusters.  In my experience even high throughput environments could have a relatively short scheduling interval in SLURM, but that of course varies from site to site.

The “quick” idea in SLURM could be achieved with something like an “interactive” partition or possibly a standing reservation.  In the past I’ve used the partition plus a matching QOS approach to help ensure interactive jobs were scheduled very quickly.  This approach worked well with the multifactor priority plugin and backfill scheduler.  A highly utilized system would likely need a standing reservation as the partition + QOS approach doesn’t necessarily guarantee jobs can be scheduled quickly unless possibly some form of preemption is used.  I’d be happy to provide examples of how I’ve done this in the past if that would help.

- Trey

--
Trey Dockendorf
HPC Systems Engineer
Ohio Supercomputer Center
From: OOD-users <ood-users-bounces+tdockendorf=osc.edu at lists.osc.edu> on behalf of "Nicklas, Jeremy" <jnicklas at osc.edu>
Reply-To: User support mailing list for Open OnDemand <ood-users at lists.osc.edu>
Date: Friday, March 23, 2018 at 1:47 PM
To: User support mailing list for Open OnDemand <ood-users at lists.osc.edu>
Subject: Re: [OOD-users] VDI

Hi Susan,

I'll take a stab at answering this. Anyone else is free to interject to add more or correct me if I am misspeak about something.

There are two "components" when it comes to our Virtual Desktop Interface (VDI) that we host here at OSC:

1. The Desktop App, which is setup and accessed just like the Jupyter and RStudio apps you are familiar with except that it launches an X11 Desktop Environment (Gnome 2, Mate, or Xfce) within the batch job and leverages a VNC server.

2. A non-advertised specialized cluster or queue/partition with a small number of compute nodes that execute single core jobs (which may be oversubscribed). This is used for Interactive Apps that do not always make full use of the processor. Some examples:

  - a desktop environment used for file editing and management
  - visualization of results in Paraview or simple web server
  - an application server that a user interacts with to setup simulations that are then submitted to the batch servers for heavy computation

For each HPC cluster at OSC (Oakley, Ruby, and Owens) we provide Desktop apps described by #1 above. We also have a non-advertised cluster called Quick that has a few Oakley, Ruby, and Owens nodes. This allows us to also provide a VDI Desktop app (described by #1 and #2 above) for each of our HPC clusters.

[cid:36f833e1-817b-4363-9b12-ffe00fa2556c]

Under the covers, the only real difference between a "Desktop" and "VDI" app shown above is that the "VDI" jobs are submitted to the Quick cluster and request a single core, whereas the "Desktop" jobs are submitted to the respective cluster and request a full node.

I'd recommend getting a Bridges Desktop app installed and running first. I'd also recommend using the Xfce desktop as I have been slowly porting our X11 GUI apps to use the tools packaged with Xfce, so you'd be able to take advantage of my work.

> Is this released yet?

Yes, the documentation to install a Desktop app is given at:

https://osc.github.io/ood-documentation/master/install-desktops.html

> How much effort to get it installed locally?

There is the initial requirements of installing TurboVNC and websockify on the compute clusters you want to run Desktops on. You also need to configure the cluster configs on your OnDemand node to point to these installation paths for the corresponding cluster. This can be a little difficult, but the good news is you only need to set this up once and it is reusable for all X11 applications you want to support in the future, e.g., MATLAB.

Then there is the Desktop App configuration, similar to the configuration you needed to do for Jupyter and RStudio with the *.yml files. Although, the Desktop app comes with the base install of OnDemand so there is less you need to configure.

Note: Because the Desktop app comes with the OnDemand installation it is highly recommended you don't modify any of the files under the installation, as they will be overwritten with future upgrades. Instead you will need to put files that override configuration under a "bc_desktop/local/" directory and keep backups of this.

Note 2: We will be releasing OnDemand 1.3 very soon and it will come with an RPM installer. The beta testers have been happy with the RPM installation so far. What does this mean for you? It means all configuration for OnDemand installed apps will be under "/etc/ood/config/apps". So remember when I told you to keep backups of "bc_desktop/local", you will now put those under "/etc/ood/config/apps/bc_desktop" when you upgrade to OnDemand 1.3. You do not need to do this now, but do keep it in the back of your head.

Also, feel free to respond with any questions you have. A variety of HPC centers currently have Desktops installed at their sites, so I am sure they will be more than happy to also help you.

--
Jeremy Nicklas
Web and Interface App Engineer
Ohio Supercomputer Center (OSC)<https://osc.edu/>
A member of the Ohio Technology Consortium<https://oh-tech.org/>
1224 Kinnear Road, Columbus, Ohio 43212
Office: (614) 292-6739<tel:+16142926739> • Mobile: (614) 316-6428<tel:+16143166428> • Fax: (614) 292-7168<tel:+16142927168>
jnicklas at osc.edu<mailto:jnicklas at osc.edu>

Learn more about OSC at https://osc.edu<https://osc.edu/>
________________________________
From: OOD-users [ood-users-bounces at lists.osc.edu] on behalf of Susan Litzinger [susan at psc.edu]
Sent: Thursday, March 22, 2018 3:11 PM
To: User support maiing list for Open OnDemand
Subject: [OOD-users] VDI
One of our staff noticed that you have Virtual Desktop Interface available through Open OnDemand.  Is this released yet?  How much effort to get it installed locally?

Thanks --

Susan Litzinger
PSC

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