v2026.1CASRAI Dictionary 714 entries across 20 domains · CC-BY 4.0714 entries · CC-BY 4.0

Dictionary termTrack CStablev2026.2

Container image (Docker/Singularity/Apptainer)

A packaged, immutable filesystem and configuration that contains an application together with all its dependencies, runnable identically on any compatible container engine (Docker, Podman, Singularity, Apptainer).

ByCASRAI Editorial Board

· Last updated 21 May 2026

Examples

Worked examples

Is an instance
An analysis distributed as a Docker image pinned by SHA-256 digest in a paper's reproducibility appendix.
Is an instance
A bioinformatics image hosted on Quay.io referenced by a Nextflow pipeline.

Counter-examples

Looks similar, but isn't

Not an instance
A virtual-machine image (heavier and less portable).
Not an instance
A conda environment YAML (specifies environment but not OS/runtime).

Editorial commentary

Container images underpin much of modern reproducibility" class="text-primary underline-offset-2 hover:underline" data-autolinked="true" title="Computational reproducibility — CASRAI Dictionary">computational reproducibility infrastructure. They are typically built from a declarative recipe (Dockerfile, def file), tagged with a version or content-addressable digest, and distributed via a registry (Docker Hub, GitHub Container Registry, Quay.io). Singularity/Apptainer add HPC-friendly features (no daemon, user-namespaced execution).

References

Open Container Initiative Image Format Specification; Kurtzer et al., 'Singularity: Scientific containers for mobility of compute' (PLOS One, 2017).

Also known as

Docker image · Singularity image · Apptainer image · OCI image

Machine-readable encodings

Use in your systems

JATS XML <role> element

xml

<role vocab="credit"
      vocab-identifier="https://casrai.org/dictionary/"
      vocab-term="Container image (Docker/Singularity/Apptainer)"
      vocab-term-identifier="https://casrai.org/dictionary/term/container-image-docker-singularity-apptainer" />

Schema.org DefinedTerm (JSON-LD)

json

{
  "@context": "https://schema.org",
  "@type": "DefinedTerm",
  "name": "Container image (Docker/Singularity/Apptainer)",
  "identifier": "https://casrai.org/dictionary/term/container-image-docker-singularity-apptainer",
  "description": "A packaged, immutable filesystem and configuration that contains an application together with all its dependencies, runnable identically on any compatible container engine (Docker, Podman, Singularity, Apptainer).",
  "inDefinedTermSet": "https://casrai.org/dictionary/domain/reproducibility-and-computational-research/",
  "url": "https://casrai.org/dictionary/term/container-image-docker-singularity-apptainer",
  "sameAs": [
    "Docker image",
    "Singularity image",
    "Apptainer image",
    "OCI image"
  ],
  "license": "https://creativecommons.org/licenses/by/4.0/"
}

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