Side by side
SingularityCE vs systemd-nspawn
Both stand on container engines. Which one you can start free with, which one lets you read the code, and what each costs once you pay.
Choose SingularityCE for free, Linux-based container packaging across HPC and other computing environments, especially when GPU support, MPI workloads, or rootless building matter. Its portable image format and Docker and OCI compatibility support varied workflows. Look elsewhere if you need Windows containers or ongoing engineering and engineering support from Sylabs after October 25, 2026.
Visit SingularityCEsystemd-nspawn provides container execution and management integrated with systemd on Linux. Review its unprivileged limits and user-namespace guidance before using it for untrusted code.
Visit systemd-nspawnThe facts
| SingularityCE | systemd-nspawn | |
|---|---|---|
| Free plan | Yes | Yes |
| Open source | Not published | Not published |
| Runs on | Linux, Self-hosted | Linux, Self-hosted |
| Lowest paid plan | Free or on request | Free or on request |
| Plans published | 1 | 1 |
| Maker | Not published | Not published |
| Website | sylabs.io | freedesktop.org |
| On container engines | #21 of 31 | #25 of 31 |
SingularityCE: what it does well
- Packages software as a portable, shareable single-file image.
- Supports compatibility with Docker and OCI container formats.
- Supports GPU workloads and high-speed interconnects.
- Containers can be built as a non-root user with fakeroot.
- PGP signing and LUKS2 encryption are supported.
What to know first
- Runs on Linux hosts.
- Windows containers are not supported.
- Sylabs plans to stop engineering and engineering support on October 25, 2026.
systemd-nspawn: what it does well
- Free to use.
- Runs directory-tree or disk-image containers.
- Can run interactively or as a system service.
- Integrates with systemd-machined and machinectl.
- Supports persistent per-container settings.
What to know first
- Requires a Linux host.
- Unprivileged use supports disk images only.
- Unprivileged networking is limited to two modes.
- Untrusted code requires a user namespace for safety.
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