Software Stacks
Available 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 Stack | Short Name | Availability | State | Lifespan | Module Software |
|---|---|---|---|---|---|
| SCC Modules | scc-lmod | SCC | active | EOL 2025 | Lmod |
| HLRN Modules | hlrn-tmod | NHR | maintenance | EOL June 2024 | Environment Modules (Tmod) |
| NHR Modules | nhr-lmod | NHR | testing | EOL 2025 | Lmod |
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).
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.
Selecting 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:
| Sub-cluster | Default | Ease of changing default |
|---|---|---|
| Emmy Phase 1/2, Grete | HLRN Modules (hlrn-tmod) | Advanced |
| Emmy Phase 3 | NHR Modules (nhr-lmod) | Simple |
Change Default on Emmy Phase 3
To set the default on Emmy Phase 3, do either of the following before /etc/profile is sourced (or, source it after you set the environmental variable or file):
- Set the environmental variable
PREFERRED_SOFTWARE_STACKto the short name of the software stack you want - Create the file
~/.unified_hpc_profilein 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.
Use NHR Modules (nhr-lmod) on Rest of NHR
It is currently not possible to have NHR Modules (nhr-lmod) loaded by default on the rest of the NHR cluster, however, it is possible to manually switch (after HLRN Modules (hlrn-tmod) has already been loaded). To do this, set your preference as you would for Emmy Phase 3 and source the unified shell profile script by running the following shell command:
source /sw/etc/profile/profile.shsource /sw/etc/profile/profile.csh