Connecting to Caviness

Use a secure shell program/client (SSH) to connect to the cluster and a secure file transfer program to move files to and from the cluster.

There are many suitable secure clients for Windows, Mac OS X, and UNIX/Linux. We recommend PuTTY and Xming for Windows users. Macintosh and UNIX/Linux users can use their pre-installed SSH and X11 software. (Newer versions of Mac OS X may not have a current version of X11 installed. See the Apple web site for X11 installation instructions.)

IT strongly recommends that you configure your clients as described in the online X-windows (X11) and SSH documents (Windows / Linux/MacOSX).

Your HPC home directory has a .ssh directory. Do not manually erase or modify the files that were initially created by the system. They facilitate communication between the login (head) node and the compute nodes. Only use standard ssh commands to add keys to the files in the .ssh directory.

Please refer to Windows and Mac/Linux related sections for specific details using the command line on your local computer:

You need a Caviness account to access the login node and it is very important to review the information about cluster accounts and cluster groups before connecting. For example, using SSH to connect to the Caviness login node with account traine, type:

    ssh traine@caviness.hpc.udel.edu

or if you need you use X-Windows requiring X11 forwarding, then use

    ssh -Y traine@caviness.hpc.udel.edu

You may set up direct SSH key authentication on Caviness once you are on the system by adding the desired public key to your authorized_keys file in the .ssh directory inside your home directory. Once you have a SSH key set up this way, you can access Caviness directly by running ssh caviness.hpc.udel.edu or ssh -Y caviness.hpc.udel.edu.

Once you are logged into Caviness, your account is configured as a member of an investing-entity group name (workgroup) which determines access to your group's compute nodes, queues and storage resources on Caviness. Setting your workgroup environment is required in order to submit jobs to the Caviness cluster. For example, the traine account is a member of the it_css workgroup. To start a shell in the it_css workgroup, type:

    workgroup -g it_css

Please review all the information regarding your computing environment especially the startup and logout scripts and using VALET. You will need to know Unix/Linux and HPC concepts before using Caviness. Use the sidebar to navigate documentation about Caviness, from accessing the cluster to running applications, using software and available training.

To learn about launching GUI applications on Caviness from a Windows machine, refer to Schedule Jobs page.

Please review the document summarizing the current resource limits and the need for and implementation of additional limits on the Caviness cluster login nodes.

When an SSH session is ended intentionally or by a loss of connectivity, you cannot generally restart it and resume your work. The UNIX screen command provides a useful solution. This command creates a virtual terminal window session that continues to run after you are logged off. It allows you to reattach the same virtual terminal window session and resume working.

Suppose you have a significant amount of interactive work to be done on the cluster, but you have an interruption coming up shortly, such as lunch. You can start a screen session and work until lunchtime. Log out and when you come back from lunch, reattach the screen session and continue your work. Even output from jobs will be displayed, as if you never left.

If you are using an unstable network connection, for example, a laptop that drops your connection when it sleeps, you may want to start a screen session before you lose connectivity.

See the man page for screen for details or review a short video How to Use the Screen Command on Linux to get started.

Connecting to Caviness

Secure shell program (SSH)

Logging on to Caviness

Screen sessions

hpc documentation