JUSTUS2/Login

Login to JUSTUS 2

Prerequisites:

You should already have

• followed the 3-step Registration procedure.
• created an account at the registration server for JUSTUS2.
• set a service password for JUSTUS2.
• set up a time-based one-time password (TOTP) for the two factor authentication (2FA)
• and you should connect from an internet address (IP) that is inside your university network (check your hostname/IP with http://displaymyhostname.com/ )

For the last point: You cannot connect directly from a computer at home to JUSTUS2. You either need to use an on-campus computer or to connect to your university via a virtual private network (VPN). Please consult the documentation of your university how to connect to your university via VPN.

Login to JUSTUS 2

When all prerequisites are fulfilled you can access the bwForCluster JUSTUS 2 for Computational Chemistry and Quantum Sciences via ssh. Only the secure shell ssh is allowed for login.

From Linux machines, you can log in using

ssh <UserID>@justus2.uni-ulm.de

During log in you must enter the current TOTP value (6-digit number) created with help of the TOTP app on your smartphone and your service password.

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

ssh -X <UserID>@justus2.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 justus2-login01.rz.uni-ulm.de, justus2-login02.rz.uni-ulm.de, justus2-login03.rz.uni-ulm.de, justus2-login04.rz.uni-ulm.de.

These names can be used to access a specific one of the login nodes. In general, you should use justus2.uni-ulm.de to allow us to balance the load over the four login nodes.

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

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.

Further reading

• Data Transfer - how to get your files on the cluster

• Scientific software is made accessible using the Environment Modules system

• Compute jobs must be submitted as Batch Jobs

• Jobs needing disk space will need to request it in their job script. See Batch Jobs - request local scratch

• What hardware is available is described in Hardware and Architecture of bwForCluster JUSTUS 2

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