Category:BwUniCluster 2.0/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.

After completing the web registration, the HPC cluster is ready for your SSH based login. The following options for SSH connections are recommended:

• Linux/MacOS: Use the ssh command (OpenSSH) in a terminal application.
• Windows: Use the MobaXterm application. Alternatively, you can use virtual machines to run native Linux applications such as SSH. An easy way to use Linux on Windows is to install the "Windows Subsystem for Linux".

1 General Login Guide

General information about logging in to the bwHPC clusters can be found in the instructions "Login to the Clusters". Please inform yourself there first. These instructions only contain the hostnames of the login nodes and other cluster-specific information.

2 Hostnames

The main hostname required to connect to bwUniCluster 2.0 is bwunicluster.scc.kit.edu or uc2.scc.kit.edu. The system has four login nodes and we use so-called DNS round-robin scheduling to load-balance the incoming connections between the nodes. If you open multiple SSH sessions to bwUniCluster 2.0, these sessions will be established to different login nodes, so processes started in one session might not be visible in other sessions.

The older Broadwell extension partition of the former bwUniCluster 1 is connected to bwUniCluster 2.0.

If you need to connect to specific login nodes, you can use the following hostnames:

3 SSH Keys

In contrast to the old bwUniCluster and many other HPC systems it is no longer possible to self-manage your SSH Keys by adding them to the ~/.ssh/authorized_keys file. Existing files will no longer be evaluated. SSH Keys have to be managed via the central bwIDM system instead. Please refer to the user guide for this functionality:

Registering SSH Keys with your Cluster

4 Troubleshooting

Issue: The "Your OTP:" prompt never appears and the connection hangs/times out instead

Likely cause: You are most likely not on a network from which access to the bwUniCluster 2.0 system is allowed. Please check if you might have to establish a VPN connection first.

Issue: The system asks for the One-Time Password multiple times

Likely cause: Make sure you are using the correct Software Token to generate the One-Time Password.

Issue: The system asks for the service password multiple times

Likely cause: Make sure you are using the service password set on bwIDM and not the password valid for your home institution. Unlike the bwUniCluster 1, the bwUniCluster 2.0 only accepts the service password.

Issue: There is an error message by the pam_ses_open.sh skript

Likely cause: Your account is in the "LOST_ACCESS" state because the entitlement is no longer valid, the questionaire was not filled out or there was a problem during the communication between your home institution and the central bwIDM system. Please try the following steps:

• Log into bwIDM, look for the bwUniCluster entry and click on Registry info. Your "Status:" should be "ACTIVE". If it is not, please wait for ten minutes since logging into the bwIDM causes a refresh and the problem might fix itself. If the status does not change to ACTIVE after a longer amount of time, please contact the support channels.

• If you have not filled out the questionaire, please do so on https://zas.bwhpc.de/shib/en/bwunicluster_survey.php and then wait for about ten minutes before attempting to log into the HPC system again.