This guide documents the Spack-based software deployment process in use by the CyberInfrastructure Services and Solutions (CISS) Group and the High-Performance Computing (HPC) User Services Group at the San Diego Supercomputer Center (SDSC). All of the definitions, conventions, policies and procedures outlined within the guide are intended to help build, maintain, and deploy custom Spack instances on the HPC systems they run and manage on behalf of end users in collaboration with the HPC Systems Group at SDSC.

• Definitions and Terminology
• General Guidelines
• About the GitHub Repository
• How to Contribute
• Miscellaneous Notes

• A Spack instance is a unique, stand-alone installation of a specific version of spack that includes custom Spack configuration files, Spack packages, and a collection of software applications, libraries, and utilities built and installed by Spack.
• A Spack package is a set of instructions that defines how a specific piece of software is compiled and/or installed by Spack. It specifies where to find and how to retrieve its software's source code, its required (and/or optional) software dependencies, its compile-time options, any patches to apply, etc. A Spack package is primarily defined by it package.py file.
• A Spack spec is a string descriptor that specifies a particular build configuration of a Spack package. The full syntax of a spec may include the package name, its version, the compiler it should be built with, the compiler version, the system architecture it should be compiled for, any compile-time options for the package, and any requirements that should be enforced on its dependencies at build time.
• The core packages of a Spack instance are those software applications, libraries, and/or utilities compiled with Spack using the default system compiler. These packages form the foundation of the software environment upon which additional Spack packages are built. In general, the core packages of a Spack instance are a set of compilers and other general software utilities. e.g., version control systems, data transfer tools, etc.
• A Spack package dependency chain is an explicitly-defined ordered set of Spack specs that share a common (core) compiler and/or MPI library, may depend on one another (or share other software dependencies), and should be installed serially one after another, one at a time, as prescribed by their dependencies.
• A Spack deployment branch is a trunk-like branch for a specific version of spack that tracks all of the Spack configuration files, Spack packages, and Spack specs used to deploy a Spack instance (or a set of instances).

The guidelines listed below are intended to provide a foundation for the conventions, policies, and procedures established by SDSC to manage its Spack instances and the software deployment process on its HPC system. While none of the guidelines are definitive and many may change over time, they should, however, be adhered to whenever possible, unless special circumstances apply.

• Any Spack instance deployed into production should originate from a deployment branch within the sdsc/spack repository.

• Any change that must be made to a Spack instance already in production should originate as a pull request submitted to one of the deployment brances within the sdsc/spack repository.

• https://spack.readthedocs.io/en/latest/contribution_guide.html

• https://spack.readthedocs.io/en/latest/packaging_guide.html

• https://spack.readthedocs.io/en/latest/developer_guide.html

The sdsc/spack GitHub repository is a custom fork of the Spack project's main spack/spack GitHub repository.

The sdsc/spack repo and its use in practice are fundamentally structured around the concept of deployment branches. A deployment branch is a trunk-like branch created from an unmodifed, official release version of spack and is named accordingly, unless special circumstances require that an intermediate commit be used. For example, the sdsc-0.17.3 deployment branch was created by checking out the v0.17.3 release

Once a version of Spack is selected and checked out, only a few minor changes and/or additions are made to the Spack release in order to initialize a deployment branch within the sdsc/spack repo. These modifications are as follows:

• The official version of the Spack README.md file is removed and replaced with the latest version of this document --- the SDSC HPC Software Deployment Guide.
• The latest version of the sdsc/spack CONTRIBUTING.md file is also included to provide information on how one may contribute to the sdsc/spack project and its deployment branches.
• A Spack package repository --- var/spack/repos/sdsc --- created to store all custom Spack packages created and/or maintained by SDSC, including all of SDSC's custom modifications to Spack's existing builtin packages.
• A Spack instance repository --- etc/spack/sdsc --- is created to ...

All other types of branches (see CONTRIBUTING.md) should start from a deployment branch.

Write access to the sdsc/spack repository is restricted to SDSC team members who are responsible for managing and tracking issues, reviewing and merging pull requests, and maintaining the custom deployment branches in the repository. All other SDSC team members who wish to contribute to the sdsc/spack repository should submit their changes via pull requests from their own public fork of the sdsc/spack repository.

etc/spack/repos.yaml var/spack/repos/sdsc/repo.yaml var/spack/repos/sdsc/packages

etc/spack/sdsc/expanse/0.17.3/cpu/specs etc/spack/sdsc/expanse/0.17.3/cpu/yamls