Helix/Login

Prerequisites

• The three bwForCluster registration steps are completed and still valid.
• Your IP address is 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.
• As credentials you need your Helix username, service password and 2FA token.
• If you encounter any issues, please have a look at the Troubleshooting section.

Login to bwForCluster Helix

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

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.

Hostnames

bwForCluster Helix has two login nodes. In general, you should stay with automatic node selection, so that the connections are evenly distributed between the login nodes. To do this, we use so-called DNS round-robin scheduling which takes care of the node balancing. This means, if you open multiple SSH sessions, these sessions may run on different login nodes. Therefore, 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

Login with SSH command (Linux, Mac, Windows)

Most Unix and Unix-like operating systems such as Linux and Mac OS as well as newer versions of MS Windows (10 and 11), have a built-in SSH client provided by the OpenSSH project. If you want to use the full set of Linux commands on Windows (10 or 11), you can also install the Windows Subsystem for Linux (WSL).

For login use one of the following ssh commands in a commandline (i.e. cmd, terminal, PowerShell):

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

To make the login process faster, tell the command that no ssh key authentication is used by adding an additional parameter:

 ssh -o PubkeyAuthentication=no <username>@helix.bwservices.uni-heidelberg.de

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.

Login with SSH key

To set up a SSH key for your workflow, read Registering SSH Keys with your Cluster. To login by using the ssh key, use the following command:

 ssh -o IdentitiesOnly=yes -i <path_to_private_key> <username>@helix.bwservices.uni-heidelberg.de 

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 with the message of the day, followed by a shell.

$ ssh -l hd_ab123 helix.bwservices.uni-heidelberg.de
Your OTP:
Password: 

********************************************************************************
*                                                                              *
*                     Baden-Wuerttemberg HPC Cluster for                       *
*              Structural and Systems Biology, Medical Science,                *
*                 Soft Matter, Computational Humanities, and                   *
*                      Mathematics and Computer Science                        *
*                                                                              *
*                                bwForCluster                                  *
*                        _    _          _   _                                 *
*                       | |  | |        | | (_)                                *
*                       | |__| |   ___  | |  _  __  __                         *
*                       |  __  |  / _ \ | | | | \ \/ /                         *
*                       | |  | | |  __/ | | | |  >  <                          *
*                       |_|  |_|  \___| |_| |_| /_/\_\                         *
*                                                                              *
*                                                                              *
*                   (xCAT 2.16.4 / RHEL 8.8 / GPFS 5.1.8)                      *
*                                                                              *
*                                                                              *
*        bwHPC Wiki : https://wiki.bwhpc.de/e/Helix                            *
*     Ticket System : https://www.bwhpc.de/supportportal                       *
*    Job Monitoring : https://helix-monitoring.bwservices.uni-heidelberg.de    *
*        E-learning : https://training.bwhpc.de/                               *
*                     -> 'Introduction to bwForCluster Helix'                  *
*                                                                              *
********************************************************************************

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

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.

Related Information

• 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.
• If you need an SSH key for your workflow, read Registering SSH Keys with your Cluster.
• Configuring your shell: .bashrc Do's and Don'ts

Troubleshooting

Login Problems

If you encounter login problems, please double check the prerequisites. If those are valid, it is fastest to first check the following points before contacting the support at the Suppport Portal. If there are known issues with the cluster, we'll inform you via e-mail or in the message of the day at the cluster.

• To reset your service password, consult the Password Guide.
• To check if your 2FA token is working go to bwServices -> "Index" -> "My Tokens".
• Make sure to not use LAN and WLAN at the same time to prevent connection problems.
• Make sure to be a fully active member of your institution.

Lost Token

To reset your token you have to visit the IT-Service to validate your identity. Mention that you want a reset of your Helix 2FA token. It is important to emphasize that the token reset is for bwForCluster Helix to avoid confusion with the token that is specific to members/students of the university of Heidelberg.

You can visit the IT service point of the URZ in person at INF 330, 69120 Heidelberg. Or you can use the video call service. It is recommended to use the Chrome browser for doing the video call. Please have on official identification ready in any case (Führerschein / Personalausweis) . For further information please see here: https://it-service.uni-heidelberg.de.

To be on the safe side, it is advised to create a backup TAN list additionally to the smartphone token.