For command line (text based) applications you will need an SSH (secure shell) client to connect. For graphical applications a graphical connection is required. We recommend Open OnDemand.

Secure shell, or SSH, is the most common method used to utliize NIH HPC systems and HPC systems in general. SSH allows you to make a secure connection to one of two "login nodes" in the Biowulf cluster to obtain a text-based terminal interface.

To access Biowulf systems via SSH or any other method, your computer must be connected to the NIH network and you will need an SSH client. Most operating installations include OpenSSH, a terminal-based SSH client which you may use to connect to Biowulf. Other, graphical SSH clients exist and may be installed by your local desktop support if desired.

Most SSH access to the Biowulf cluster is through the main login node biowulf.nih.gov, suitable for job submission, management, and preparation. Access for file management and transfer should use the Helix login node helix.nih.gov. Comptuationally-intense work must be performed on compute nodes through the Slurm job management system.

For more information and detailed guides on how to connect to NIH HPC systems with SSH, consult our SSH guidance.

As an alternative to the text-based interface provided by SSH, NIH HPC offers an Open OnDemand service which enables you to access any HPC resources securely using your web browser with no software installation or configuration necessary. You may access Open OnDemand directly at hpcondemand.nih.gov if you are on the NIH network.

Open OnDemand offers the ability to do all of the following in your web browser:

• Access a terminal interface similar to that for SSH.
• Access a graphical desktop-like environment running on the cluster.
• Directly launch and access interactive tools including Jupyter, RStudio, and Visual Studio Code.
• View your files and data and perform basic file management with a web interface.

Accessing Open OnDemand requires NIH multi-factor authentication utilizing PIV card authentication or Microsoft Authenticator set up for your account.

Globus is an option for interacting with HPC systems for the purpose of file transfer and management. Although Globus does not offer the ability to interact with compute or job management, it is the recommended method for file transfers and management. Globus may be accessed via your web browser or with a dedicated desktop application.

You may find more information on utilizing Globus in our Globus documentation.

Are you on the NIH network or the VPN?

If not, you will not be able to connect to Biowulf or Helix. A simple test if you are on VPN is to point your web browser to this test page. If you see 'Access forbidden!', then you are not on the VPN.

Is your Biowulf/Helix account locked?

Your account may be locked due to inactivity. If you are on the NIH network or the VPN, you can check the status and unlock it yourself by going to the User Dashboard. If you are unable to access the dashboard, send email to staff@hpc.nih.gov asking for your account to be unlocked.

If you are on the VPN or the NIH network, and your account is unlocked, and you are still not able to connect, please send the following information to the HPC staff (staff@hpc.nih.gov):

• what kind of computer and Operating System you’re connecting from
• what software are you using to connect and which version? (e.g. PuTTY, command-line SSH, Open OnDemand)
• what was the error message?