Add 2nd Blog post on Spack+EESSI, + corrections to 1st by lorisercole · Pull Request #675 · EESSI/docs

lorisercole · 2026-02-05T14:48:34Z

No description provided.

ocaisa

Looks good!

docs/blog/posts/2026/02/Spack-on-top-of-EESSI-best-of-both-worlds.md

ocaisa · 2026-02-05T15:17:19Z

docs/blog/posts/2026/02/Spack-on-top-of-EESSI-best-of-both-worlds.md

+
+## Demo code
+
+A demonstrated implementation of the presented approach is now available in the [EasySpack repository](https://github.com/lorisercole/easyspack).


I think there are copyright issues with that repo name (I believe @tgamblin mentioned something like this a while ago), might be best to change it already before we publish.

uh, I did not remember it! Let's wait for @tgamblin to confirm.
In case I can change it to something like EessiSpack (and I'll need to change some code... 😅)

I think it is more about the Spack in the name due to HPSF and copyright

Yeah basically they don't want Spack in the name -- to avoid confusion with Spack itself (which one should I use? EasySpack or Spack? Sure sounds like the first one's better). LF trademark policy is here if you are interested: https://lfprojects.org/policies/trademark-policy/

So... yeah... it would be good to change the name. Sorry I realize that is a pain. Some alliterative ideas:

Spoke (spokes out from the central EESSI hub to enable Spack)

Spanner (spans two ecosystems)

Spork (serves two functions)

Or less alliterative:

PELT - Package Ecosystem Linking Tool

PLATO - Package Linking Atlantic Treaty Organization

I think I should stop with that one. I'll see myself out. I guess you could also call it the "EESSI connector for Spack" or something like that, which is boring but straight from the trademark policy. I feel like there has to be a cool name for this.

You could also just name the repo Spack-on-top-of-EESSI, since that's exactly what it is, no trademark violation there imho.

I LOL'ed at Spork, that's just too good :D

I think that actually runs afoul of the policy b/c it's not spack -- you can call your thing "X for spack", "X compatible with Spack", etc. but not "Spack". There are examples in the policy. If the LF mark is the primary noun it's dicey.

boegel · 2026-02-05T18:48:29Z

docs/blog/posts/2026/02/easyspack-demo-1.webp

I'm not going to block the publication of the blog post for this, but we should consider using asciinema for this, like I did here: https://www.eessi.io/docs/blog/2026/02/04/EESSI-at-FOSDEM-26/#eessi-cli-tool

boegel · 2026-02-05T18:49:19Z

docs/blog/posts/2026/02/Spack-on-top-of-EESSI-best-of-both-worlds.md

+
+The HPC software landscape offers powerful tools for managing scientific software, such as [EasyBuild](https://easybuild.io) and [Spack](https://spack.io).
+
+[EESSI](https://www.eessi.io) provides a ready-to-use software stack with thousands of optimized packages built with EasyBuild. 


Suggested change

[EESSI](https://www.eessi.io) provides a ready-to-use software stack with thousands of optimized packages built with EasyBuild.

[EESSI](https://www.eessi.io) provides a ready-to-use software stack with thousands of optimized software installations that were built with EasyBuild.

boegel · 2026-02-05T18:50:05Z

docs/blog/posts/2026/02/Spack-on-top-of-EESSI-best-of-both-worlds.md

+
+[EESSI](https://www.eessi.io) provides a ready-to-use software stack with thousands of optimized packages built with EasyBuild. 
+
+Imagine you are working on an HPC system with EESSI already available. You have access to a wealth of optimized scientific software packages, libraries, tools, as well as compilers. But you need to install a new tool or a specific version of a package that's not in EESSI yet.


Suggested change

Imagine you are working on an HPC system with EESSI already available. You have access to a wealth of optimized scientific software packages, libraries, tools, as well as compilers. But you need to install a new tool or a specific version of a package that's not in EESSI yet.

Imagine you are working on an HPC system with EESSI already available. You have access to a wealth of optimized installations for scientific software packages, libraries, tools, as well as compilers. But you need to install a new tool or a specific version of a package that's not in EESSI yet.

boegel · 2026-02-05T18:57:34Z

docs/blog/posts/2026/02/Spack-on-top-of-EESSI-best-of-both-worlds.md

+Imagine you are working on an HPC system with EESSI already available. You have access to a wealth of optimized scientific software packages, libraries, tools, as well as compilers. But you need to install a new tool or a specific version of a package that's not in EESSI yet.
+
+You can already extend EESSI with new software through the [EESSI-extend](https://www.eessi.io/docs/using_eessi/building_on_eessi/#building-software-on-top-of-eessi-with-easybuild) module.
+This utility provides you with a pre-configured EasyBuild installation that you can use to build packages from [EasyConfig files](https://docs.easybuild.io/terminology/#easyconfig_files).


Suggested change

This utility provides you with a pre-configured EasyBuild installation that you can use to build packages from [EasyConfig files](https://docs.easybuild.io/terminology/#easyconfig_files).

This utility provides you with a pre-configured EasyBuild installation that you can use to build packages from [easyconfig files](https://docs.easybuild.io/terminology/#easyconfig_files).

boegel · 2026-02-05T19:00:13Z

docs/blog/posts/2026/02/Spack-on-top-of-EESSI-best-of-both-worlds.md

+
+Imagine you are working on an HPC system with EESSI already available. You have access to a wealth of optimized scientific software packages, libraries, tools, as well as compilers. But you need to install a new tool or a specific version of a package that's not in EESSI yet.
+
+You can already extend EESSI with new software through the [EESSI-extend](https://www.eessi.io/docs/using_eessi/building_on_eessi/#building-software-on-top-of-eessi-with-easybuild) module.


use internal link:

Suggested change

You can already extend EESSI with new software through the [EESSI-extend](https://www.eessi.io/docs/using_eessi/building_on_eessi/#building-software-on-top-of-eessi-with-easybuild) module.

You can already extend EESSI with new software through the [EESSI-extend](../../../../using_eessi/building_on_eessi.md) module.

boegel · 2026-02-05T19:01:22Z

docs/blog/posts/2026/02/Spack-on-top-of-EESSI-best-of-both-worlds.md

+In a previous [blog post](https://www.eessi.io/docs/blog/2026/01/09/Spack-on-top-of-EESSI-PoC/), we presented a first proof-of-concept implementation of this vision. 
+We used a custom-built upstream database to make Spack aware of EESSI's software stack and managed to build a new Quantum ESPRESSO installation that reused dependencies from EESSI.
+
+Thanks to recent updates to Spack (in particular, treating externals as concrete specs and allowing the definition of dependencies – see [this PR](https://github.com/spack/spack/pull/51118)) and an active collaboration with its developers, it is now possible to connect Spack and EESSI in a *seamless* and *Spack-native* way.


Suggested change

Thanks to recent updates to Spack (in particular, treating externals as concrete specs and allowing the definition of dependencies – see [this PR](https://github.com/spack/spack/pull/51118)) and an active collaboration with its developers, it is now possible to connect Spack and EESSI in a *seamless* and *Spack-native* way.

Thanks to recent updates to Spack (in particular, treating externals as concrete specs and allowing the definition of dependencies – see [this pull request in Spack](https://github.com/spack/spack/pull/51118)) and an active collaboration with its developers, it is now possible to connect Spack and EESSI in a *seamless* and *Spack-native* way.

boegel · 2026-02-05T19:15:49Z

docs/blog/posts/2026/02/Spack-on-top-of-EESSI-best-of-both-worlds.md

+It is possible to detect OS packages available under the EESSI compat-layer and configure Spack to use them as externals.
+In EESSI, these packages are often dependencies of software-layer packages (see previous example), so it is suggested to include them.


Suggested change

It is possible to detect OS packages available under the EESSI compat-layer and configure Spack to use them as externals.

In EESSI, these packages are often dependencies of software-layer packages (see previous example), so it is suggested to include them.

It is possible to detect software installations available in the EESSI compatibility layer and configure Spack to use them as externals.

In EESSI, these are often dependencies of software installations in the software layer (see previous example), so it is suggested to include them.

boegel · 2026-02-05T19:16:16Z

docs/blog/posts/2026/02/Spack-on-top-of-EESSI-best-of-both-worlds.md

+This utility provides you with a pre-configured EasyBuild installation that you can use to build packages from [EasyConfig files](https://docs.easybuild.io/terminology/#easyconfig_files).
+
+Like EasyBuild, [Spack](https://spack.io) is a flexible build tool that also offers a vast repository of build recipes maintained by a large and active community, making it a familiar tool for many HPC users.
+By enabling Spack to leverage packages already available in EESSI as dependencies, we can offer users the best of both worlds: the convenience of a pre-built, optimized software stack combined with the flexibility to quickly build new packages using tools they already know.


Suggested change

By enabling Spack to leverage packages already available in EESSI as dependencies, we can offer users the best of both worlds: the convenience of a pre-built, optimized software stack combined with the flexibility to quickly build new packages using tools they already know.

By enabling Spack to leverage software installations already available in EESSI as dependencies, we can offer users the best of both worlds: the convenience of a pre-built, optimized software stack combined with the flexibility to quickly build new packages using tools they already know.

boegel · 2026-02-05T19:17:09Z

docs/blog/posts/2026/02/Spack-on-top-of-EESSI-best-of-both-worlds.md

+
+This can be done automatically via `spack external find`:
+
+![Detect compat-layer packages with spack external find](spack-eessi-20260205-002.webp)


This could also be a small asciinema box.

Big advantage here is that you can see it "move", but also that you can copy-paste from it...

boegel · 2026-02-05T19:19:58Z

docs/blog/posts/2026/02/Spack-on-top-of-EESSI-best-of-both-worlds.md

+
+Finally, we can proceed with the installation with `spack install quantum-espresso~mpi`:
+
+![Installing Quantum ESPRESSO with Spack on top of EESSI](spack-eessi-20260205-006.webp)


Also here we can use asciinema, and just play it at 10x speed... :)

boegel · 2026-02-05T19:22:31Z

docs/blog/posts/2026/02/Spack-on-top-of-EESSI-best-of-both-worlds.md

+
+### Acknowledgements
+
+This work was made possible thanks to the collaboration with the Spack development team, in particular Todd Gamblin and Massimiliano Culpo, as well as EESSI team members Kenneth Hoste and Alan O'Cais.


Bonus points if you link these to GitHub profiles ;-)

lorisercole added 2 commits February 2, 2026 18:31

corrections to 1st Spack+EESSI blog post

02e890e

Write 2nd blog post on Spack+EESSI

3485e51

ocaisa requested changes Feb 5, 2026

View reviewed changes

address a few comments

c695add

boegel reviewed Feb 5, 2026

View reviewed changes

boegel requested changes Feb 5, 2026

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		## Demo code

		A demonstrated implementation of the presented approach is now available in the [EasySpack repository](https://github.com/lorisercole/easyspack).


		The HPC software landscape offers powerful tools for managing scientific software, such as [EasyBuild](https://easybuild.io) and [Spack](https://spack.io).

		[EESSI](https://www.eessi.io) provides a ready-to-use software stack with thousands of optimized packages built with EasyBuild.


		[EESSI](https://www.eessi.io) provides a ready-to-use software stack with thousands of optimized packages built with EasyBuild.

		Imagine you are working on an HPC system with EESSI already available. You have access to a wealth of optimized scientific software packages, libraries, tools, as well as compilers. But you need to install a new tool or a specific version of a package that's not in EESSI yet.

	This utility provides you with a pre-configured EasyBuild installation that you can use to build packages from [EasyConfig files](https://docs.easybuild.io/terminology/#easyconfig_files).
	This utility provides you with a pre-configured EasyBuild installation that you can use to build packages from [easyconfig files](https://docs.easybuild.io/terminology/#easyconfig_files).


		Imagine you are working on an HPC system with EESSI already available. You have access to a wealth of optimized scientific software packages, libraries, tools, as well as compilers. But you need to install a new tool or a specific version of a package that's not in EESSI yet.

		You can already extend EESSI with new software through the [EESSI-extend](https://www.eessi.io/docs/using_eessi/building_on_eessi/#building-software-on-top-of-eessi-with-easybuild) module.

	Thanks to recent updates to Spack (in particular, treating externals as concrete specs and allowing the definition of dependencies – see [this PR](https://github.com/spack/spack/pull/51118)) and an active collaboration with its developers, it is now possible to connect Spack and EESSI in a seamless and Spack-native way.
	Thanks to recent updates to Spack (in particular, treating externals as concrete specs and allowing the definition of dependencies – see [this pull request in Spack](https://github.com/spack/spack/pull/51118)) and an active collaboration with its developers, it is now possible to connect Spack and EESSI in a seamless and Spack-native way.

		It is possible to detect OS packages available under the EESSI compat-layer and configure Spack to use them as externals.
		In EESSI, these packages are often dependencies of software-layer packages (see previous example), so it is suggested to include them.

	By enabling Spack to leverage packages already available in EESSI as dependencies, we can offer users the best of both worlds: the convenience of a pre-built, optimized software stack combined with the flexibility to quickly build new packages using tools they already know.
	By enabling Spack to leverage software installations already available in EESSI as dependencies, we can offer users the best of both worlds: the convenience of a pre-built, optimized software stack combined with the flexibility to quickly build new packages using tools they already know.


		This can be done automatically via `spack external find`:

		![Detect compat-layer packages with spack external find](spack-eessi-20260205-002.webp)


		Finally, we can proceed with the installation with `spack install quantum-espresso~mpi`:

		![Installing Quantum ESPRESSO with Spack on top of EESSI](spack-eessi-20260205-006.webp)


		### Acknowledgements

		This work was made possible thanks to the collaboration with the Spack development team, in particular Todd Gamblin and Massimiliano Culpo, as well as EESSI team members Kenneth Hoste and Alan O'Cais.

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lorisercole commented Feb 5, 2026

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tgamblin Feb 5, 2026 •

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