Logging In

Here, you’ll find DNS names for our login nodes, sorted by cluster, their hostkey fingerprints and some examples showing how you can connect from the command line.

The Login Nodes

Names and Aliases

The proper DNS names of all frontend nodes and convenient aliases are provided in the table below. For square brackets with a number range, substitute any number in the range.

The SCC jumphosts are not part of the HPC clusters, but are needed to reach the SCC login nodes from outside GÖNET if you are not using VPN/Wireguard. Their DNS names and convenient aliases are in the table below:

SSH key fingerprints

When first connecting, SSH will warn you that the host’s key is unknown and to make sure that it is correct, in order to avoid man-in-the-middle attacks. The following table contains all SHA-256 fingerprints of the host keys of the login nodes and jumphosts, arranged by key algorithm:

Example Logins with OpenSSH

Logging into an SCC login node

With the .ssh/config file setup as in the Simple configuration examples, one would run just ssh SCC. If using the inside GÖNET config, the terminal session could look something like

jdoe1@laptop:~> ssh SCC
Enter passphrase for key '/home/jdoe1/.ssh/id_ed25519':
Last login: Wed Mar 20 09:05:45 2024 from 192.168.0.1
gwdu101:90 15:58:26 ~ >

If using the jumphost, it could look something like

jdoe1@laptop:~> ssh SCC
Enter passphrase for key '/home/jdoe1/.ssh/id_ed25519':
Enter passphrase for key '/home/jdoe1/.ssh/id_ed25519':
Last login: Wed Mar 20 09:05:45 2024 from 192.168.0.1
gwdu102:90 15:58:26 ~ >

If you are not using a configured Host entry (not recommended) or want to know how to connect “manually” (useful for troubleshooting), here is how you would do so (using a jumphost):

ssh jdoe1@login-mdc.hpc.gwdg.de -i .ssh/id_ed25519 -J jdoe1@login.gwdg.de

Or, if you are using an older SSH client:

ssh jdoe1@login-mdc.hpc.gwdg.de -i .ssh/id_ed25519 -o ProxyCommand="ssh -i .ssh/id-rsa -W %h:%p jdoe1@login.gwdg.de"

Make sure to replace jdoe1 with your actual username.

Logging into an NHR Grete login node

With the .ssh/config file setup as in the Simple configuration examples, one would run just ssh Grete. The terminal session could look something like

jdoe1@laptop:~> ssh Grete
Enter passphrase for key '/home/jdoe1/.ssh/id_ed25519':
Last login: Wed Mar 20 09:05:45 2024 from 192.168.0.1

********************************************************************************
*                                                                              *
*                     Welcome to HLRN-IV site Goettingen,                      *
*                     this is node glogin10 on "Emmy".                         *
*                                                                              *
*  Documentation  ->  https://www.hlrn.de/doc/                                 *
*  Support        ->  mailto:nhr-support@gwdg.de                               *
*                                                                              *
********************************************************************************

Found "/scratch/usr/gzadmfnord", setting $WORK
Found "/scratch/tmp/gzadmfnord", setting $TMPDIR
Module sw.skl loaded.
Module slurm (current version 23.11.4) loaded.
Module HLRNenv loaded.

Loading HLRNenv
  Loading requirement: sw.skl slurm
glogin10:~ $

Logging into a specific node

This is essential if one needs to

• Reconnect to a tmux or screen session
• Reconnect to a session started by an IDE over SSH
• Use a dedicated login node for one’s research group (for those with such a login node)
• Use a login node with particular hardware

With the .ssh/config file setup as in the Advanced configuration examples for all nodes configured individually, you would run just ssh NODE where NODE is the name of the node or a suitable alias.