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Access to bwForCluster Helix is only possible from IP addresses within the BelWü network which connects universities and other scientific institutions in Baden-Württemberg. If your computer is in your University network (e.g. at your office), you should be able to connect to bwForCluster Helix without restrictions. If you are 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.

Prerequisites for successful login:

You need to have

1 Login to bwForCluster Helix

Login to bwForCluster Helix 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 Helix 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 ab123 and you are a user from Heidelberg University, your username on the cluster is: hd_ab123.

1.2 Hostnames

bwForCluster Helix has two login nodes. We use so-called DNS round-robin scheduling to load-balance the incoming connections between the nodes. If you open multiple SSH sessions, these sessions may run on different login nodes, so processes started in one session might not be visible in other sessions.

Hostname Destination
helix.bwservices.uni-heidelberg.de one of the two login nodes

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.

For login use one of the following ssh commands:

ssh <username>@helix.bwservices.uni-heidelberg.de
ssh -l <username> helix.bwservices.uni-heidelberg.de

To run graphical applications on the cluster, you need to enable X11 forwarding with the -X flag:

ssh -X -l <username> helix.bwservices.uni-heidelberg.de

1.4 Login with graphical SSH client (Windows)

For Windows we suggest using MobaXterm for login and file transfer.

Start MobaXterm and fill in the following fields:

Remote name              : helix.bwservices.uni-heidelberg.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 Helix, 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 hd_ab123 helix.bwservices.uni-heidelberg.de
Your OTP:

*                                                                              *
*                     Baden-Wuerttemberg HPC Cluster for                       *
*              Structural and Systems Biology, Medical Science,                *
*                  Soft Matter, and Computational Humanities                   *
*                                                                              *
*                                bwForCluster                                  *                    
*                        _    _          _   _                                 *
*                       | |  | |        | | (_)                                *
*                       | |__| |   ___  | |  _  __  __                         *
*                       |  __  |  / _ \ | | | | \ \/ /                         *
*                       | |  | | |  __/ | | | |  >  <                          *
*                       |_|  |_|  \___| |_| |_| /_/\_\                         *
*                                                                              *
*                                                                              *
*                    (xCAT 2.16.4 / RHEL8.5 / GPFS 5.1.2)                      *
*                                                                              *
*                 bwHPC Wiki: https://wiki.bwhpc.de/e/Helix                    *
*              Ticket System: https://www.bwhpc.de/supportportal               *
*                                                                              *

Last login: ...
[hd_ab123@login ~]$ 

2 Allowed Activities on Login Nodes


To guarantee usability for all users 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 notice. Long-running compilation or long-running pre- or post-processing tasks must also be submitted as batch jobs.

The login nodes are the access points to the compute system, your $HOME directory and your workspaces. These nodes are shared with all users. Hence, your activities on the login nodes are primarily limited to setting up your batch jobs. Your activities may also be:

  • quick compilation of program code or
  • quick pre- and post-processing of results from batch jobs.

We advise to use interactive batch jobs for compute and memory intensive compilation and pre- and post-processing tasks.

3 Related Information