Spack installation


  • Interpreter for Spack:

    • Python 2.7 or Python 3.5–3.9

  • Building software

    • C/C++ compilers

    • make, patch and bash

  • Create and extract archives

    • tar, gzip and bzip

  • Manage software repositories

    • git

  • Sign and verify Build caches

    • gnupg2

$ sudo apt install build-essential patch tar gzip bzip2 git gnupg2
$ xcode-select --install
$ brew install make bash gzip bzip2 git gnupg
$ brew link gnupg


To install Spack the repository is cloned and then changed from the develop branch to the branch of the current release, in our case to v0.17.1:

$ git clone
Cloning into 'spack'...
$ cd spack
$ git switch v0.19

Configure the shell

  1. To configure the bash environment, the following is entered in the ~/.bashrc:

    export SPACK_ROOT=~/spack
    . $SPACK_ROOT/share/spack/
  2. The changed configuration is read with

    $ source ~/.bashrc

Bootstrapping clingo

Spack uses clingo to resolve optimal versions and variants of dependencies when installing packages. To install clingo from pre-built binaries you can simply specify a package:

$ spack spec zlib
 ==> Bootstrapping clingo from pre-built binaries
 ==> Fetching
 ==> Fetching
 ==> Installing "clingo-bootstrap@spack%gcc@10.2.1~docs~ipo+python+static_libstdcpp build_type=Release arch=linux-centos7-x86_64" from a buildcache
Input spec

zlib@1.2.13%gcc@11.3.0+optimize+pic+shared build_system=makefile arch=linux-ubuntu22.04-sandybridge


When bootstrapping from pre-built binaries, Spack requires patchelf on Linux or otool on macOS. Otherwise Spack built it from sources and with a C++ compiler.

Bootstrap store

All tools Spack needs are installed in a separate store, which lives in the $HOME/.spack directory. The software installed there can be queried with:

$ spack find --bootstrap
==> Showing internal bootstrap store at "/srv/jupyter/.spack/bootstrap/store"
==> 3 installed packages
-- linux-rhel5-x86_64 / gcc@9.3.0 -------------------------------
clingo-bootstrap@spack  python@3.8

-- linux-ubuntu20.04-sandybridge / gcc@9.3.0 --------------------

Compiler configuration

$ spack compilers
 ==> Available compilers
 -- gcc ubuntu22.04-x86_64 ---------------------------------------

Build your own compiler

$ spack install gcc
==> gcc: Successfully installed gcc-11.2.0-azhiay4ugfrs634hqlez7u3f2li3wvzd
  Fetch: 12.09s.  Build: 2h 8m 13.92s.  Total: 2h 8m 26.01s.
[+] /Users/veit/spack/opt/spack/darwin-bigsur-cannonlake/apple-clang-13.0.0/gcc-11.2.0-azhiay4ugfrs634hqlez7u3f2li3wvzd

However, Spack doesn’t find the compiler at first:

$ spack compilers
==> Available compilers
-- gcc ubuntu20.04-x86_64 ---------------------------------------

Now, you can add the compiler with spack compiler find:

$ spack compiler find /srv/jupyter/spack/opt/spack/linux-ubuntu22.04-sandybridge/gcc-11.3.0/gcc-12.2.0-gbaw464qxjuz6i3uud42cd5mb4xujxia/
 ==> Added 1 new compiler to /srv/jupyter/.spack/linux/compilers.yaml
 ==> Compilers are defined in the following files:

spack compilers should now also find the newly installed compiler:

$ spack compilers
 ==> Available compilers
 -- gcc ubuntu22.04-x86_64 ---------------------------------------
 gcc@12.2.0  gcc@11.3.0

If you want to overwrite the default and site settings, you can edit $HOME/.spack/packages.yaml:

    compiler: [gcc@12.2.0]

GPG signing

Spack supports the signing and verification of packages with GPG keys. A separate key ring is used for Spack, why no keys are available from users’ home directories.

When Spack is first installed, this key ring will be empty. The keys stored in /var/spack/gpg are the standard keys for a Spack installation. These keys are imported by spack gpg init. This will import the standard keys into the keyring as trusted keys.

Trust keys

Additional keys can be added to the key ring using spack gpg trust <keyfile>. Once a key is trusted, packages signed by the owner of that key can be installed.

Create a key

You can also create your own keys to be able to sign your own packages with

$ spack gpg export <location> [<key>…]

List keys

The keys available in the keyring can be listed with

$ spack gpg list

Remove a key

Keys can be removed with

$ spack gpg untrust <keyid>

Key IDs can be email addresses, names or fingerprints.