Connecting to Mantis

In order to connect to the Mantis cluster, you must use an SSH client. See below for instructions based on your operating system.

Warning

When you connect to Mantis, you will be connected to a login node. Please do not do any serious computation on these nodes. To do real work, submit a batch job or request an interactive session. Long running or intensive processes found on login nodes may be killed without notice.

Internal Host URL

If you connect to the CAM virtual private network, the cluster can be accessed through this host url:

mantis-submit.cam.uchc.edu

Tip

This host will drop you onto one of four login nodes, labeled mantis-sub-[1-4]. If the redirect fails, you can try logging in directly to one of them:

  • mantis-sub-1.cam.uchc.edu
  • mantis-sub-2.cam.uchc.edu
  • mantis-sub-3.cam.uchc.edu
  • mantis-sub-4.cam.uchc.edu

TODO: Appropriate/accurate to say something about load balancing here

The internal host is planned to be phased out in the near future so that only the external host explained below will be used.

External Host URL

The cluster can also be accessed through an external login host available from anywhere (on/off campus, with/without VPN). This host does not allow password authentication, however, so to use it you must set up an ssh key.

The host URL is:

login.hpc.cam.uchc.edu

Tip

As above, this url will redirect you to one of these hosts:

  • mantis-sub-5.cam.uchc.edu
  • mantis-sub-6.cam.uchc.edu
  • mantis-sub-7.cam.uchc.edu

If the redirect fails, you can try logging in directly to one of them.

Using SSH Client

An ssh client is installed by default on Mac and Linux operating sytems and can be run from the Terminal App.

Connecting

To create a connection, enter the ssh command followed by your username and host url like so. Login with

ssh <user>@<host>

TODO: How to do this

TODO: How to do this

VPN

To connect to the CAM VPN, follow the instructions here.

Note that the CAM VPN is distinct from the University VPN.

SSH Keys

SSH keys are a secure authentication method that can be used for remote access to a server without needing passwords. It is in fact a more secure authentication method than using a password. SSH keys consist of a pair of cryptographic keys - a private key kept secret on your computer and a public key placed on the remote server you want to access.

Creating a public private key pair.

You can create an SSH key pair To create an SSH key pair to use with the cluster, use the following command:

ssh-keygen -t ed25519 -C <comment>

The comment should be something to help you identify which computer this key comes from. For example <user>-laptop

You will be prompted to specify the location to save the key. You can press enter to accept the default location.

Next you will be prompted to create a passphrase which is optional. If you don’t wish to create a passphrase, simply press enter.

Copy to Mantis

After creating a key pair or if you have an existing one that you want to use, you can copy it to the cluster with the following command:

ssh-copy-id <user>@mantis-submit.cam.uchc.edu

TODO: How to do this on Windows

SSH Tunnelling

TODO: Explain why you might need this and how to do it.

X11 Forwarding

TODO: Why you might need this and how to do it.