= Registration bwUniCluster =

The bwUniCluster is the universal cluster for tier 3 high performance computing (HPC) in Baden-Württemberg.
It is co-financed by the Ministry of Science, Research and the Arts Baden-Württemberg and the shareholders.

All members of the shareholder universities can apply for an account:

* Universität Freiburg
* Universität Heidelberg
* Universität Hohenheim
* Karlsruhe Institute of Technology (KIT)
* Universität Konstanz
* Universität Mannheim
* Universität Stuttgart
* Universität Tübingen
* Universität Ulm
* [[Registration/HAW|HAW BW e.V.]] (an association of several universities of applied sciences in Baden-Württemberg)

The use of the bwUniCluster is free of charge.

== Three Steps for Registration ==

[[File:bwUniCluster-Registration.png|thumb|right|upright=1.3|bwUniCluster Registration Process]]

The registration process for the bwUniCluster is divided into three steps:

* Step A: You need to get the '''bwUniCluster Entitlement''' from your university/college. → '''[[Registration/bwUniCluster/Entitlement|Step A: bwUniCluster Entitlement]]
* Step B: You need to fill out the '''bwUniCluster questionnaire'''. → '''[[Registration/bwUniCluster/Questionnaire|Step B: bwUniCluster Questionnaire]]

* Step C: You need to '''register for the service bwUniCluster''' (create an account on the cluster). → '''[[Registration/bwUniCluster/Service|Step C: bwUniCluster Registration]]

----

After finishing Step C, you are done with registration.

* To '''login''' to the bwUniCluster, see our → '''[[Registration/Login|Login Guide]]'''

== Information for registered users ==

* Please refer to cluster-specific pages for [[bwUniCluster 3.0]] (also accessible via the overview links on the left).
* If you want to check if your '''account''' is still valid on the bwUniCluster, please refer to the general → '''[[Registration/Account|Account Guide]]'''
* If you want to '''create a second factor''', please refer to → '''[[Registration/2FA|Generate a Second Factor (2FA)]]'''
* If you need to '''change or forgot your password''' for the bwUniCluster, please refer to the general → '''[[Registration/Password|Password Guide]]'''
* If you want to '''use SSH keys''' on the bwUniCluster, please refer to → '''[[Registration/SSH|Registering SSH Keys with your Cluster]]'''
* If you want do '''de-register your user account''' from the bwUniCluster, please refer to the general → '''[[Registration/Deregistration|De-registration Guide]]'''

== Contact / Support ==

If you have questions or problems concerning the bwUniCluster registration, please [[BwUniCluster3.0/Support|contact your local hotline]].

2026-03-25T09:09:52Z

K Siegmund: /* Link to Batch System per Cluster */

← This page is used in the [[HPC Glossary]] to explain the term "Batch Scheduler" and "Batch System"
== Life Cycle of a Calculation (Job) ==
[[File:running_calculations_on_cluster.svg|thumb|upright=0.4]]
On your desktop computer you start your calculations and they start immediately, running until they are finished. Then your desktop does mostly nothing, until you start another calculation. A compute cluster has several hundred, maybe a thousand computers (compute nodes), all of them are busy most of the time and many people want to run a great number of calculations. So running your job has to include some extra steps:

# prepare a script (a set commands to run - usually as a shell script), with all the commands that are necessary to run your calculation from start to finish. In addition to the commands necessary to run the calculation, this ''[[batch script]]'' has a header section, in which you specify details like required compute cores (processing units witin a computer), estimated runtime, memory requirements, disk space needed, etc.
# ''Submit'' the script into a queue, where your ''job'' (calculation)
# gets asigned an inital priority, is queued and waits in row with other compute jobs until the resources you requested in the header become available. (Requested time is also a resource!)
# Execution: Once a suitable resource slot is available and your job is in the front of the queue of suitable jobs (suitable with regards to the resource slot), your script is executed on (a) compute node(s). Your calculation runs on that/those node(s) until it is finished or reaches the specified time limit.
# Save results: Include commands to save the calculation results back to a long term storage (e.g. your home directory), at least at the end of your script. What you have not saved until the job finishes won't be saved!
# If your job reaches the specified time limit, all your running processes will be killed and the resources get cleared. So any data that has not been saved will be lost!

The software that distributes jobs on compute nodes is called a '''[[batch system]]''' or '''batch scheduler'''. The software currently used as a [[batch system]] on bwHPC clusters is "Slurm".

Learn more about the functioning of job distribution in

→ '''[[batch system]]'''

== Example Jobs ==

For most software that a bwHPC project installed on the cluster, we have prepared an example job script running some example calculation with that exact software.

How to access these examples is described in the "Software job examples" section of the page

→ '''[[Environment Modules]]'''

== Job Script and Job Submission ==

Batch jobs are submitted with the command:

<syntaxhighlight lang="bash">$ sbatch <job-script> </syntaxhighlight>

A job script contains options for Slurm in lines beginning with #SBATCH as well as your commands which you want to execute on the compute nodes. For example:

<syntaxhighlight lang="slurm">#!/bin/bash
#SBATCH --partition=<cluster specific>
#SBATCH --ntasks-per-node=8
#SBATCH --time=00:05:00
#SBATCH --mem=1gb
#SBATCH --export=NONE
echo 'Here would start your calculation script'
</syntaxhighlight>

Please see cluster specific examples from the links in the next section, because exact options needed differ by cluster.

== Link to Batch System and Examples per Cluster ==

Because of differences in configuration (partly due to different available hardware), each cluster has their own batch system documentation:

→ '''[[BwUniCluster3.0/Running_Jobs|Slurm bwUniCluster 3.0]]'''

→ '''[[JUSTUS2/Jobscripts: Running Your Calculations | Slurm JUSTUS 2]]'''

→ '''[[Helix/Slurm | Slurm Helix]]'''

→ '''[[NEMO2/Slurm | Slurm NEMO2]]'''

→ '''[[BinAC2/Slurm | Slurm BinAC2]]'''

== How to Use Computing Ressources Efficiently ==

When you are running your calculations, you will have to decide on how many compute-cores your job will be simultaneously calculated.
For this, your computational problem will have to be divided into pieces, which always causes some overhead.

How to find a reasonable number of how many compute cores to use for your calculation can be found under

→ '''[[Scaling]]'''

Running calculations on an HPC node consumes a lot of energy. To make the most of the available resources and keep cluster and energy use as efficient as possible please also see our advice for

→ '''[[Energy Efficient Cluster Usage]]'''

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