diff --git a/docs/blog/.authors.yml b/docs/blog/.authors.yml index 99ca665b91..55b09ad45b 100644 --- a/docs/blog/.authors.yml +++ b/docs/blog/.authors.yml @@ -139,5 +139,8 @@ authors: description: MattX avatar: https://avatars.githubusercontent.com/u/574106 slug: https://github.com/krisbuytaert - - + adrianreber: + name: Adrian Reber + description: Amutable + avatar: https://avatars.githubusercontent.com/u/8724298?v=4 + slug: https://github.com/adrianreber diff --git a/docs/blog/posts/2026/11/eessi-in-openhpc-4.2.md b/docs/blog/posts/2026/11/eessi-in-openhpc-4.2.md new file mode 100644 index 0000000000..b0ee7d2b29 --- /dev/null +++ b/docs/blog/posts/2026/11/eessi-in-openhpc-4.2.md @@ -0,0 +1,118 @@ +--- +authors: [adrianreber] +date: 2026-11-01 +slug: eessi-in-openhpc-4.2 +--- + +# EESSI in OpenHPC 4.2 + +
+![OpenHPC](ohpc_logo.png){width=50%} +
+ +[OpenHPC](https://openhpc.community/) 4.2 was +[released on 1 November 2026](https://openhpc.community/news/2026/openhpc-v4-2-release-additional-provisioners-resource-managers-and-module-systems/). +Among the new material in the install guide is an optional section that sets up +[EESSI](../../../../index.md) on the cluster being built: the CernVM-FS client +on the head node and in the compute image, the `software.eessi.io` repository, +and a module that makes the EESSI software stack available through the usual +`module` commands. + + + +## A long-standing connection + +OpenHPC and the EasyBuild community have been in contact for a long time. +EasyBuild has been packaged in OpenHPC since late 2016 and is still part of +OpenHPC 4.2, alongside Spack, for sites that prefer to build their own +software. EESSI, in turn, grew out of that same community: its +[software layer](../../../../software_layer.md) is built with EasyBuild, and +the installations are exposed through Lmod. + +The integration of EESSI in OpenHPC 4.2 is therefore not a first encounter +between two unrelated projects, but an existing connection becoming visible in +the install guide, where site administrators are likely to come across it. + +It followed from several conversations over the past few years about bringing +the two projects closer together. While working on OpenHPC 4.2 I returned to +the idea, and integrating EESSI proved easier than expected. The section was +written on the OpenHPC side and reviewed by the EESSI project. + +## What it does + +Administrators who want EESSI on their cluster can enable the section when +preparing the installation. The recipe then installs the CernVM-FS client and +the EESSI configuration on the head node and in the compute image, and adds an +`eessi` module to the OpenHPC module hierarchy. From that point on, the +standard EESSI workflow applies: + +```console +[test@sms ~]$ module load eessi +[test@sms ~]$ module avail EESSI + +-------------------- /cvmfs/software.eessi.io/init/modules --------------------- + EESSI/2023.06 (D) EESSI/2025.06 EESSI/2026.06 + + Where: + D: Default Module + +[test@sms ~]$ module load EESSI/2026.06 +[test@sms ~]$ module avail +``` + +The final `module avail` deserves attention. A freshly installed OpenHPC +cluster already provides a substantial set of packages, but EESSI adds +[more than 900 software projects](../../../../available_software/index.md) on +top of it, built for the CPU architecture of the node on which the job runs, +none of which has to be compiled at the site. For a cluster being set up today, +this removes a considerable amount of work before users can start. + +The EESSI section is part of the recipe templates like every other section, and +the test matrix includes configurations with `enable_eessi` set, so it is +covered by the same integration testing as the rest of the guide. OpenHPC 4.2 +was validated with 172,794 tests over 306 hours. + +## Points to consider before enabling it + +Two points are worth highlighting before enabling the section: + +- **The integration as implemented in OpenHPC 4.2 relies on Lmod.** EESSI + ships its initialization modules as Lua modulefiles, which only Lmod reads. + OpenHPC 4.2 also offers Environment Modules 5.7 as an alternative module + system, but with that selected the repository still mounts and its files + remain usable directly, while the EESSI modules cannot be loaded by + Environment Modules. EESSI itself does ship Lmod, so it remains possible to + [initialise and use EESSI as per the standard usage instructions](../../../../using_eessi/setting_up_environment.md); + without additional configuration, however, this would clobber the + Environment Modules environment. Explicit support for Environment Modules is + so far a + [proposal](https://modules.readthedocs.io/en/latest/design/eessi.html) in the + Environment Modules documentation rather than something EESSI currently + provides. +- **A proxy is recommended in production.** The recipe configures clients with + `CVMFS_USE_CDN=yes`, so that content is fetched through a CDN rather than + directly from the EESSI mirror servers. This is adequate for a test cluster + and keeps the load on those servers low, but a production cluster should run + a local Squid proxy and point the clients at it with `CVMFS_HTTP_PROXY`. See + the EESSI documentation on + [native installation on clusters](../../../../getting_access/native_installation.md#native-install-on-clusters). + +## Reading the section + +OpenHPC 4.2 includes a +[Recipe Explorer](https://openhpc.github.io/ohpc/4.2/explorer/): after +selecting a base OS, architecture, provisioner and resource manager, and +enabling the optional features, it renders the corresponding install guide +together with a `recipe.sh` and an `input.local`. The EESSI section for an +AlmaLinux 10 / x86_64 / Warewulf / Slurm cluster is available +[here](https://openhpc.github.io/ohpc/4.2/explorer/#almalinux10-x86_64-warewulf-slurm?chapter=eessi); +for a different combination, enable EESSI in the options on the left and the +section appears in the table of contents. + +## Questions + +Questions about OpenHPC itself are best raised on the +[OpenHPC](https://github.com/openhpc/ohpc) issue tracker. Questions about EESSI, +such as missing software or problems with the CernVM-FS repository, should be +directed to the EESSI project through the channels listed on the +[support page](../../../../support.md). diff --git a/docs/blog/posts/2026/11/ohpc_logo.png b/docs/blog/posts/2026/11/ohpc_logo.png new file mode 100644 index 0000000000..989dff3818 Binary files /dev/null and b/docs/blog/posts/2026/11/ohpc_logo.png differ