Software Stacks

Each cluster has one or more software stacks providing ready to use software beyond what is included in the base OS of the frontend and compute nodes, which are listed in the table below. All three listed stacks are module-based systems. See Module Basics for more information on how to use modules.

Software StackShort NameAvailabilityStateLifespanModule Software
SCC Modulesscc-lmodSCCactiveEOL 2025Lmod
HLRN Moduleshlrn-tmodNHRmaintenanceEOL June 2024Environment Modules (Tmod)
NHR Modulesnhr-lmodNHRactiveEOL 2025Lmod
Note

You will notice that currently, no software stack is available on both the SCC and NHR clusters. This will change when the clusters are unified later in 2024 with the new unified software stack. The new software stack will subsume the NHR Modules (nhr-lmod) and SCC Modules (scc-lmod) software stacks as available revisions (the nhr-lmod and scc-lmod aliases will be retained).

Tip

Most 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.

Both SCC Modules (scc-lmod) and NHR Modules (nhr-lmod) have modules compiled for several different CPU and fabric architectures in use in the GWDG clusters and automatically pick the version optimized for the type of node where the module is loaded.

Select a Preferred Stack

SCC

There is only one stack, SCC Modules (scc-lmod), so there is nothing to select. There are, however, different revisions available, see the respective section on that page.

NHR

There are two software stacks available, HLRN Modules (hlrn-tmod) (now in maintenance mode) and NHR Modules (nhr-lmod) (new stack in testing). Each stack is the default in a different part of the cluster depending on the OS.

Sub-clusterNHR Modules (nhr-lmod)HLRN Modules (hlrn-tmod)
Emmy Phase 2defaultavailable
Emmy Phase 3defaultavailable
Grete Phase 1defaultavailable
Grete Phase 2defaultavailable
Grete Phase 3defaultavailable (untested)

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