Software Stacks

There are software stacks providing ready to use software beyond what is included in the base OS of the login and compute nodes, which are listed in the table below. The default software stack and which ones will work depends on the cluster island. All three listed stacks are module-based systems. See Module Basics for more information on how to use modules.

Software StackShort NameStateLifespanModule Software
NHR Modulesnhr-lmodactiveEOL 2025/Q2Lmod
SCC Modulesscc-lmodactiveEOL 2025/Q2Lmod
HLRN Moduleshlrn-tmodretired, partially brokenEOL June 2024Environment Modules (Tmod)

Both the SCC Modules (scc-lmod) and NHR Modules (nhr-lmod) software stacks have modules compiled for several different CPU, GPU, and fabric architectures in use in the GWDG clusters and automatically pick a version optimized or at least compatible for the type of node where the module is loaded. The default software stack for each island and their states for the island are listed in the table below

Sub-clusterDefaultnhr-lmodscc-lmodhlrn-tmod
Emmy Phase 3nhr-lmod✅untesteduntested, partially broken
Emmy Phase 2nhr-lmod✅untestedpartially broken
Emmy Phase 1nhr-lmod✅untestedpartially broken
Grete Phase 3nhr-lmod✅untesteduntested, partially broken
Grete Phase 2nhr-lmod✅untestedpartially broken
Grete Phase 1nhr-lmod✅untestedpartially broken
SCC Legacy (CPU)scc-lmoduntested✅untested, partially broken
SCC Legacy (GPU)scc-lmod❌✅untested, partially broken
CIDBNscc-lmod❌✅untested, partially broken
FGscc-lmod❌✅untested, partially broken
SOEscc-lmod❌✅untested, partially broken
Note

You will notice that currently, there is no software stack that works on all islands. A new unified software stack will be released in 2025/Q1 or 2025/Q2 that will work on all islands, which will work the same way as the current NHR Modules (nhr-lmod) software stack.

Info

See CPU Partitions and GPU Partitions for the available partitions in each island for each kind of account.

See Logging In for the best login nodes for each island (other login nodes will often work, but may have access to different storage systems and their hardware will be less of a match).

See Cluster Storage Map for the storage systems accessible from each island and their relative performance characteristics.

See Types of User Accounts if you are unsure what kind of account you have.

Tip

Some of the currently available software package documentation refers to the HLRN Modules (hlrn-tmod) software stack (see that page for the packages), but most details still apply to their equivalent modules in the other software stacks.

Select a Preferred Stack

Change Default

To set the default, do either of the following before /etc/profile is sourced (or, source it after you set the environmental variable or file):

  1. Set the environmental variable PREFERRED_SOFTWARE_STACK to the short name of the software stack you want
  2. Create the file ~/.unified_hpc_profile in your HOME directory and write the short name of your preferred software stack to the file (e.g. echo hlrn-tmod > ~/.unified_hpc_profile).

If both are set, the value in PREFERRED_SOFTWARE_STACK takes priority.

Note that if the preferred software stack is not available for some reason, /etc/profile will fallback to whatever is available.

Changing Stack Mid-Session

You can also at any point change the software stack you are using in your current shell session by setting the PREFERRED_SOFTWARE_STACK environmental variable to the desired value and then sourcing the unified shell profile script by running the following shell commands (substitute in your desired software stack name):

Load prefered software stack:
export PREFERRED_SOFTWARE_STACK=DESIRED_STACK
source /sw/etc/profile/profile.sh
setenv PREFERRED_SOFTWARE_STACK DESIRED_STACK
source /sw/etc/profile/profile.csh