Apptainer

Apptainer is an open-source HPC containerization platform that runs rootless, daemonless containers with first-class support for MPI, GPU passthrough, and shared HPC filesystems. Warewulf Pro distributes a CIQ-packaged build of Apptainer that adheres closely to the upstream version but may include bugfixes ahead of the upstream release.

Why Apptainer is bundled with Warewulf Pro

Two reasons:

HPC workloads commonly use containers. Bundling Apptainer means the same Depot entitlement that gets you Warewulf also gets you the HPC-native runtime your users will run inside the cluster.
Pro node images use Apptainer. The OpenHPC-derived Pro images (rockylinux-ohpc, rockylinux-slurm, rockylinux-openpbs) come with Apptainer pre-installed and the apptainer overlay pre-wired for rootless operation.

Installation

Apptainer is in the warewulf-pro Depot repository:


# depot enable warewulf-pro
# dnf -y install apptainer

If you only need Apptainer (not Warewulf), this is still the supported installation path under your Pro entitlement.

Version policy

Warewulf Pro tracks upstream Apptainer releases:

An upstream Apptainer patch release prompts a Warewulf Pro patch release.
An upstream Apptainer minor release prompts a Warewulf Pro minor release.
An upstream Apptainer major release prompts a Warewulf Pro major release.

The currently bundled Apptainer version is noted in each release notes entry.

Documentation

For Apptainer usage - building images, running containers, MPI integration, GPU passthrough - see the upstream Apptainer documentation.

The apptainer Pro overlay configures rootless support on cluster nodes; see that page for the cluster-side wiring.

Pro node images Overview