On both Casper and Derecho, CISL uses the Spack package manager to install compilers and software libraries for you to use. You are probably familiar with these software packages from using our modules system. However, you may not know that you can also augment our software stack with your own package installs using Spack. It provides the concept of “chained installations”, in which there is a downstream instance of Spack (i.e. yours) that can use packages from an upstream instance (the CISL software stack) as dependencies.

To make it easier to set up such a downstream, CISL provides a utility called spack-downstream, which will create a copy of Spack in your work directory and configure it to interact with our upstream version. Spack supports thousands of software packages, and the best part is that any package you install can show up alongside our software packages as a module. Check out our Spack documentation to get started using this new capability!