BwUniCluster2.0/Login

Access to bwUniCluster 2.0 is limited to IP addresses from the BelWü network. All home institutions of our current users are connected to BelWü, so if you are on your campus network (e.g. in your office or on the Campus WiFi) you should be able to connect to bwUniCluster 2.0 without restrictions. If you are outside one of the BelWü networks (e.g. at home), a VPN connection to the home institution or a connection to an SSH jump host at the home institution must be established first.

The login nodes of the bwHPC clusters are the access point to the compute system, your $HOME directory and your workspaces. All users must log in through these nodes to submit jobs to the cluster.

Prerequisites for successful login:

You need to have

• completed the 3-step registration procedure.
• set a service password for bwUniCluster 2.0.
• set up a second factor for the time-based one-time password (TOTP).

1 Login to the bwUniCluster

Login to the bwUniCluster 2.0 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 general information on SSH clients, visit the SSH clients Guide.

1.1 Username

If you want to use the bwUniCluster 2.0 you need to add a prefix to your local username. Users from the KIT, don't need a prefix on the bwUniCluster. For prefixes please refer to the Username Wiki.

Examples:

• If your local username for the University is vwxyz1234 and you are a user from the University of Freiburg this would combine to: fr_vwxyz1234.
• If your KIT username is pxd27239, you can use the same username for the bwUniCluster.

1.2 Hostnames

The system has four login nodes. The selection of the login node is done automatically. If you are logging in multiple times, different sessions might run on different login nodes.

Login to bwUniClister 2.0:

Hostname	Node type
bwunicluster.scc.kit.edu	login to one of the four login nodes
uc2.scc.kit.edu	login to one of the four login nodes

In general, you should use automatic selection to allow us to balance the load over the four login nodes. If you need to connect to specific login nodes, you can use the following hostnames:

Hostname	Node type
uc2-login1.scc.kit.edu	bwUniCluster 2.0 first login node
uc2-login2.scc.kit.edu	bwUniCluster 2.0 second login node
uc2-login3.scc.kit.edu	bwUniCluster 2.0 third login node
uc2-login4.scc.kit.edu	bwUniCluster 2.0 fourth login node

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

Most Unix and Unix-like operating systems like Linux, Mac OS and *BSD 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>@bwunicluster.scc.kit.edu
ssh -l <username> uc2.scc.kit.edu

To run graphical applications, you can use the -X or -Y flag to ssh:

ssh -Y -l <username> bwunicluster.scc.kit.edu

For better performance, we recommend using VNC.

1.4 Login with graphical SSH client (Windows)

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

Start MobaXterm, fill in the following fields:

Remote name              : bwunicluster.scc.kit.edu    # or uc2.scc.kit.edu
Specify user name        : <username>
Port                     : 22

After that click on 'ok'. Then a terminal will be opened and there you can enter your credentials.

1.5 Login Example

To log in to bwUniCluster 2.0, you must provide your service password. Proceed as follows:

1. Use SSH for a login node.
2. The system will ask for a one-time password Your OTP:. Please enter your OTP and confirm it with Enter/Return. 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. 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 fr_vwxyz1234 bwunicluster.scc.kit.edu
(fr_vwxyz1234@bwunicluster.scc.kit.edu) Your OTP: 123456
(fr_vwxyz1234@bwunicluster.scc.kit.edu) Password: 
********************************************************************************
*        _             _   _       _  ____ _           _            ___        *
*       | |____      _| | | |_ __ (_)/ ___| |_   _ ___| |_ ___ _ __(__ \       *
*       | '_ \ \ /\ / / | | | '_ \| | |   | | | | / __| __/ _ \ '__| / /       *
*       | |_) \ V  V /| |_| | | | | | |___| | |_| \__ \ ||  __/ |   / /_       *
*       |_.__/ \_/\_/  \___/|_| |_|_|\____|_|\__,_|___/\__\___|_|  (____|      *
*                                                                              *
*                   (KITE 2.0, RHEL 8.4, Lustre 2.12.6_ddn72)                  *
*                                                                              *
*                      wiki: https://wiki.bwhpc.de/e/bwUniCluster_2.0          *
*                                                                              *
*             ticket system: https://www.bwhpc.de/supportportal                *
*                     email: bwunicluster@bwhpc.de                             *
*                                                                              *
*                  training: https://training.bwhpc.de                         *
*                     email: training@bwhpc.de                                 *
*                                                                              *
********************************************************************************
Last login: Thu Jul  7 18:09:43 2022 from host1.scc.kit.edu
********************************************************************************
[fr_vwxyz1234@uc2n995 ~]$ 

1.6 Troubleshooting

See bwUniCluster FAQ.

2 Allowed Activities on Login Nodes

To guarantee usability for all the users of clusters you must not run your compute jobs on the login nodes. Compute jobs must be submitted to the queuing system. Any compute job running on the login nodes will be terminated without any notice. Any long-running compilation or any long-running pre- or post-processing of batch jobs must also be submitted to the queuing system.

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

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

We advise users to use interactive jobs for compute and memory intensive tasks like compiling.

3 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.
• If you need an SSH key for your workflow, read Registering SSH Keys with your Cluster.