BwForCluster Chemistry Login

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Contents

1 Login

After registration (registration procedure at bwForCluster User Access, the bwForCluster Chemistry can be accessed via ssh. Only the secure shell ssh is allowed for login.

From linux machines, you can log in using

ssh <UserID>@justus.uni-ulm.de

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

ssh -X <UserID>@justus.uni-ulm.de

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


The bwForCluster Chemistry in Ulm has four dedicated 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.

The names of the four login nodes are justus-login01.rz.uni-ulm.de, justus-login03.rz.uni-ulm.de, justus-login02.rz.uni-ulm.de, justus-login04.rz.uni-ulm.de.

These names can be used to access a specific one of the login nodes. In general, you should use justus.uni-ulm.de to allow us to balance the load over the four login nodes.


1.1 About UserID / Username

<UserID> of the ssh command is a placeholder for your username at your home organization and a prefix denoting your organization. Prefixes and resulting user names are as follows:

Site Prefix Username
Freiburg fr fr_username
Heidelberg hd hd_username
Hohenheim ho ho_username
Karlsruhe ka ka_username
Konstanz kn kn_username
Mannheim ma ma_username
Stuttgart st st_username
Tübingen tu tu_username
Ulm ul ul_username

1.2 Allowed activities on login nodes

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.


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.

2 Further reading