Spack

Spack is an open-source package manager designed for high-performance computing (HPC). It enables the building, installation, and management of scientific software across diverse hardware, operating systems, compilers, and configurations, helping to create reproducible software stacks for research and development.

Spack uses Python-based package definitions (Package.py) and a large catalog of packages. Users express a software requirement as a spec that names a package, a version, and optional variants and dependencies. Spack concretizes the spec into a concrete DAG, selecting specific versions and compiler options, and installs the resulting prefixes. Its architecture supports multiple compilers, virtual dependencies (such as MPI providers), and variants to customize builds. Spack can generate environment setup via modules or lmod to facilitate loading software.

To promote reproducibility and sharing, Spack builds are isolated in unique prefixes keyed by the spec hash. It supports mirrors and binary caches to accelerate installations. Typical workflows include spack install, spack spec to inspect dependencies, spack load to configure the environment, and spack env to manage sets of related packages. The project maintains a central repository of package recipes and allows extending with local or external packages.

Spack originated at Lawrence Livermore National Laboratory in the mid-2010s and has since been adopted by many research centers and institutions. It is released under the BSD 3-clause license and is actively developed by an open-source community.