8. Constructing Environments

This section describes the environments (environment specs) defined in spack/var/spack/repos/jcsda-emc-bundles/packages, additional packages available in the JCSDA/NOAA-EMC spack fork, as well as pre-defined application templates and container recipes.

Environments can be constructed in two ways in spack-stack:

  1. Start with an empty template, spack stack create env --template=empty --compiler=<compiler> or just spack stack create env --compiler=<compiler> without specifying a template.

    • Configure the environment as shown in Sections 6.

    • Ensure that <compiler> corresponds to a valid compiler for the site. Examples are gcc, intel, apple-clang, oneapi.

    • Add spack packages (also referred to as specs) to the environment using spack add. These packages can be virtual environments described in Section 8.2 below, or individual packages, e.g. esmf or atlas. Examples:

      spack add netcdf-c@4.7.4
spack add ufs-weather-model-env
spack add ufs-weather-model-env@1.0.0 +debug
spack add ewok-env
spack add mapl@2.12.3 +debug ^esmf@8.3.0 +debug
spack add mapl@2.12.3 +debug ^esmf@8.3.0 +debug
...

  2. Use a non-empty template to automatically populate the environment with a vetted combination of packages. See Section 8.3 for a description of the available templates. Note that additional packages can be added to the templated environment as in the previous step after activating the environment. Example:

    spack stack create env --template=skylab-1.0.0 --compiler=<compiler>
...
cd envs/env-name
spack env activate .
...
spack add jedi-tools-env@1.0.0

8.1. Additional packages

Packages that are available in the JCSDA/NOAA-EMC spack fork, but not (yet) in the authoritative spack repository are defined in spack-ext/repos/spack-stack/packages/. Users are encouraged to run spack info <packagename> or open the files in an ASCII editor for more information.

8.2. Virtual packages

The purpose of virtual packages is to provide a convenient collection of packages for a given application. These packages are also defined in spack-ext/repos/spack-stack/packages/. Users are encouraged to run spack info <packagename> or open the files in an ASCII editor for more information.

8.3. Templates

Templates are vetted combinations of packages, i.e. these have been tested to build together. Templates are defined in configs/templates/. Users are encouraged to inspect these templates in an ASCII editor for more information.