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Access to the bwForCluster is only possible from IP addresses within the BelWü network. If your computer is in your University network (e.g. at your office), you should be able to connect directly. From outside the BelWü network (e.g. at home), a VPN (virtual private network) connection to your University network must be established first. Please consult the VPN documentation of your University. You can learn your current hostname/IP at e.g. https://myhostname.net/

Prerequisites for successful login:

You need to have

1 Login to JUSTUS 2

Login to bwForCluster bwForCluster JUSTUS 2 is only possible with a Secure Shell (SSH) client for which you must know your username on the cluster and the hostname of the login nodes. For more gneral information on SSH clients, visit the SSH clients Guide.

1.1 Username

Your username on bwForCluster JUSTUS 2 consists of a prefix and your local username. For prefixes please refer to the Username Guide.

Example: If your local username at your University is ab12 and you are a user from Ulm University, your username on the cluster is: ul_abc12.

1.2 Hostnames

JUSTUS 2 has four login nodes. We use DNS round-robin scheduling to load-balance the incoming connections between the nodes. If you are logging in multiple times, different sessions might run on different login nodes and hence programs started in one session might not be visible in another sessions.

Hostname Destination
justus2.uni-ulm.de any one of the login nodes
justus2-login01.rz.uni-ulm.de login node 01
justus2-login02.rz.uni-ulm.de login node 02
justus2-login03.rz.uni-ulm.de login node 03
justus2-login04.rz.uni-ulm.de login node 04

Note: justus2-login02.rz.uni-ulm.de serves as test environment for internal use and is omitted in DNS round-robin.

There are further two visualization nodes for use with VNC:

Hostname Destination
justus2-vis.uni-ulm.de any one of the visualization nodes
justus2-vis01.rz.uni-ulm.de vis node 01
justus2-vis02.rz.uni-ulm.de vis node 02

1.3 Login with SSH command (Linux, Mac, Windows)

Most Unix and Unix-like operating systems like Linux or MacOS come with a built-in SSH client provided by the OpenSSH project. More recent versions of Windows 10 and Windows 11 using the Windows Subsystem for Linux (WSL) also come with a built-in OpenSSH client.

From those machines, you can log in using:

ssh <username>@justus2.uni-ulm.de

During log in you must enter the current TOTP value (6-digit number) created with help of the TOTP app on your smartphone and your service password.

To run graphical applications, you can use the -X flag to openssh:

ssh -X <username>@justus2.uni-ulm.de

For better performance on slow connections you should use e.g. VNC.

1.4 Login with graphical SSH client (Windows)

Example MobaXterm for login and file transfer:

Start MobaXterm and fill in the following fields:

Remote name              : justus2.uni-ulm.de
Specify user name        : <username>
Port                     : 22

After that click on 'ok'. Then a terminal will open where you can enter your credentials.

1.5 Login Example

To login to bwForCluster JUSTUS 2, proceed as follows:

  1. Login with SSH command or MoabXterm as shown above.
  2. The system will ask for a one-time password Your OTP:. Please enter your OTP and confirm it with Enter/Return. The OTP is not displayed when typing. If you do not have a second factor yet, please create one (see Registration/2FA).
  3. The system will ask you for your service password Password:. Please enter it and confirm it with Enter/Return. The password is not displayed when typing. If you do not have a service password yet or have forgotten it, please create one (see Registration/Password).
  4. You will be greeted by the cluster, followed by a shell.
$ ssh -l ul_abc12 justus2.uni-ulm.de
Your OTP:

*                                                                              *
*                     Baden-Wuerttemberg Research Cluster                      *
*                 Computational Chemistry and Quantum Sciences                 *
*                                                                              *
*                                 bwForCluster                                 *
*                                                                              *
*              __   __  __   _____  ______   __  __   _____      ___           *
*             / /  / / / /  / ___/ /_  __/  / / / /  / ___/     |__ \          *
*        __  / /  / / / /   \__ \   / /    / / / /   \__ \      __/ /          *
*       / /_/ /  / /_/ /   ___/ /  / /    / /_/ /   ___/ /     / __/           *
*       \____/   \____/   /____/  /_/     \____/   /____/     /____/           *
*                                                                              *
*                                                                              *
*                   (Rocky 8 / Kernel 4.18 / Lustre 2.12)                      *
*                                                                              *
*                       https://wiki.bwhpc.de/e/JUSTUS2                        *
*                                                                              *
*               ticket system: https://www.bwhpc.de/supportportal              *
*                                                                              *
Last login: ...
[ul_abc12@login01 ~]$ 

1.6 Allowed Activities on Login Nodes

To guarantee usability for all users of the bwForCluster you must not run your compute jobs on the login nodes. Compute jobs must be submitted as

Batch Jobs. Any compute job running on the login nodes will be terminated without any notice.

The login nodes are the access point to the compute system and its $HOME directory. The login nodes are shared with all the users of the cluster. Therefore, your activities on the login nodes are limited to primarily set up your batch jobs. Your activities may also be:

  • compilation of your program code and
  • short pre- and postprocessing of your batch jobs.

2 Related Information

  • If you want to reset your service password, consult the Password Guide.
  • If you want to register a new token for the two factor authentication (2FA), consult the 2FA Guide.
  • If you want to de-register, consult the De-registration Guide.