Apptainer vs systemd-nspawn
Apptainer
apptainer.orgsystemd-nspawn
freedesktop.orgSide by side
| Figure | Apptainer | systemd-nspawn |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Windows | Yes | — |
| macOS | Yes | — |
| Linux | Yes | Yes |
| API | Yes | — |
| Self-hosted | Yes | Yes |
| Plans published | 1 | 1 |
| Spec score · Container Engines | 8.9 (#1) | 7.5 (#18) |
| Purpose | Apptainer creates and runs containers that package software for portability and reproducibility. | systemd-nspawn runs a command or a full Linux-based operating system in a lightweight namespace container. |
| Support | Free support resources include Slack, a mailing list, and GitHub, while commercial support and services are offered through CIQ. | The systemd project lists its mailing list, IRC channel, and Matrix channel as support options. |
Plans
In their own words
Apptainer
Apptainer is a free container platform for creating and running portable, reproducible workloads, with a focus on shared systems and high-performance computing. It packages containers as immutable, single-file Singularity Image Format (SIF) images designed for transport and sharing. By default, users retain the same privileges inside and outside containers. Images can be signed and verified with PGP keys, PEM keys or X.509 certificates, and encrypted containers can run without writing decrypted contents to disk. Apptainer imports containers from OCI registries and aims to support most Docker Hub containers without changes. It can expose host resources such as GPUs, high-speed networks and parallel filesystems, and supports NVIDIA CUDA, AMD ROCm, Intel Gaudi and OCI Container Device Interface accelerators. Running Apptainer requires Linux; Windows and macOS need a Linux virtual machine, with Windows also listed via WSL2. Root access is unnecessary when user namespaces are available. Full functionality requires kernel support for FUSE and unprivileged user namespaces. Community support includes Slack, Google Groups and GitHub, with commercial services through CIQ.
systemd-nspawn
systemd-nspawn has no write-up on Specifiction yet; its figures are above.