Apptainer vs containerd
Apptainer
apptainer.orgcontainerd
containerd.ioSide by side
| Figure | Apptainer | containerd |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Windows | Yes | Yes |
| macOS | Yes | — |
| Linux | Yes | Yes |
| API | Yes | — |
| Self-hosted | Yes | Yes |
| Plans published | 1 | 1 |
| Spec score · Container Engines | 8.9 (#1) | 8.0 (#9) |
| Spec score · Container Runtime Software | 8.9 (#1) | 8.1 (#11) |
| Purpose | Apptainer creates and runs containers that package software for portability and reproducibility. | containerd is an industry-standard container runtime for managing a host’s container lifecycle, including image transfer and storage, execution, and supervision. |
| Support | Free support resources include Slack, a mailing list, and GitHub, while commercial support and services are offered through CIQ. | Nightly builds are available for Linux and Windows, but may contain critical bugs, are not recommended for production, and receive no support. |
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.
containerd
containerd is a free container runtime for managing a host’s container lifecycle. It handles image transfer and storage, execution, and supervision, and is designed to be embedded in a larger system rather than used directly by developers or end users. It supports OCI images and image push and pull operations, and uses runc by default while allowing other OCI-compliant runtimes. Its built-in CRI plugin can make it the container runtime for a Kubernetes cluster, and it supports registries compliant with the OCI Distribution Specification. The daemon is available for Linux and Windows. Network-interface management and image building are outside containerd’s first-class scope, so higher-level systems or tools handle those jobs. Its ctr command-line tool is intended for development and debugging, without a guarantee of a stable interface or a human-friendly experience. Users typically also need runc and CNI plugins. The plan is free; free plan available, with no free trial.