NIH HPC hosts an Open OnDemand installation to allow for interactive access, similar to what is possible with Nomachine or SSH tunneling, to the HPC cluster with a secure web-based interface.

The Open OnDemand interface allows you to work on the Biowulf cluster via your web browser. You can utilize select interactive web applications like Jupyter, RStudio or VS Code directly without logging in via traditional SSH. You can also access graphical applications via a familiar interface running on compute nodes.

The NIH HPC Open OnDemand service does not currently support direct batch job submission. You can perform job submission through many of the interactive applications offered via this service.

Although basic file access and management may be done through the Open OnDemand File Browser, we recommend any large file transfer be done through Globus, accessible via the "Globus" link at the top of the File Browser menu.

Applications available via the Open OnDemand interface include (but aren't limited to):

Graphical applications can be accessed directly in your browser via a Nomachine-like interface:

Other applications are accessible via Open OnDemand and more will likely be added in the future. If you have an application you would like to see added, please reach out to staff@hpc.nih.gov.

We currently recommend against using Apple Safari to access Open OnDemand, particularly if you intend to use the Graphical Session feature. There are a few issues around clipboard access and some Graphical Applications. If you experience difficulties using Safari, we recommend trying another browser. See the FAQ below for more information.

To connect to the HPC Open OnDemand installation, you will need to be connected to the NIH network, either on-campus or via the VPN and either a smart card (PIV) or the use of multi-factor authentication (MFA). When you open the HPC OnDemand website in your browser you will be redirected to the NIH central login page where you will need to sign in either with your smart card or with your MFA authenticator app. Successfully logging in will redirect you to the Open OnDemand home page.

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To actually utilize Biowulf resources through Open OnDemand, you will need to launch a Slurm job on the cluster through the web interface. There are a selection of our most commonly used applications available directly on the landing page.

Most Applications utilize an "interactive job" on Biowulf to launch the application. You are still limited to two concurrent interactive jobs on the Biowulf cluster. Applications such as Jupyter, RStudio, and VSCode do count as one of your allotted interactive sessions. The "Graphical Session", which provides the desktop-like experience, is the major exception. You are allotted a single Graphical Session through Open OnDemand. This Graphical Session does not count against your allotted interactive jobs on Biowulf.

To access our complete list of applications you can do several things. You can click on the "Interactive Apps" button in the blue top menu bar to access a dropdown. You can also click on the link "all available apps" next to Pinned Apps. Finally, you will be able to see our applications available in a sidebar on the My Interactive Sessions page, also accessible from the menu bar. This page will also show you your running, pending, and past OnDemand jobs and allow you to (re)connect to any currently-running jobs.

All Open OnDemand jobs run on compute nodes with dedicated resources. You can do anything you could do in a standard job that is appropriate to run on HPC resources.

Notably, and unlike Nomachine, the Graphical Session jobs run with (limited) dedicated resources and you can feel free to run real computational workloads or analysis directly in those sessions without any issues as with operating on the login nodes Biowulf or Helix.

Other applications provided in Open OnDemand allow you to perform analysis, development, or visualization in much the same way you would use similar applications with sinteractive and SSH tunneling.

The Graphical Session jobs providing VNC access to an XFCE desktop provide a fixed amount of resources for seven days. All other applications currently run as standard Biowulf interactive jobs with configurable resources and walltime and have the same maximum time of 36 hours.

You get one dedicated Graphical session job per user. Other interactive applications run as standard Biowulf interactive jobs (like sinteractive) and share the two simultaneous job limit. If you already have two sessions, whether in Open OnDemand or via sinteractive, any additional jobs will fail to submit. Use of the Open OnDemand dashboard itself does not utilize any Slurm resources.

There are known issues with some of the underlying technology used to make certain OnDemand applications function and the Safari web browser. These issues are known to cause copy and paste between some graphical applications, including the Graphical Sessions, interactive shell, and Matlab, to not function as intended. Applications such as RStudio, Jupyter, and VSCode are not known to be affected by this issue at this time. If you choose to use Safari to access OnDemand and you encounter unexcepted behavior in an application, you should first try a different web browser to see if the issue persists.

Why do I get certificate erros when accessing from Linux? ("your connection is not private")

The HPC OnDemand service is available only internally on the NIH network and uses an internal TLS certificate. Your system and/or browser must be configured to trust the Federal Common Policy CA G2 root certificate. While it is not necessary for this service, we also recommend you install the NIH DPKI root certificate to facilitate using other internal NIH services.