Skopeo

skopeo is a command line utility that performs various operations on container images and image repositories.

Usage

Inspecting a repository

skopeo is able to inspect a repository on a container registry and fetch images layers. The inspect command fetches the repository’s manifest and it is able to show you a docker inspect-like json output about a whole repository or a tag. This tool, in contrast to docker inspect, helps you gather useful information about a repository or a tag before pulling it (using disk space). The inspect command can show you which tags are available for the given repository, the labels the image has, the creation date and operating system of the image and more.

Show properties of fedora:latest

$ skopeo inspect docker://registry.fedoraproject.org/fedora:latest
{
    "Name": "registry.fedoraproject.org/fedora",
    "Digest": "sha256:0f65bee641e821f8118acafb44c2f8fe30c2fc6b9a2b3729c0660376391aa117",
    "RepoTags": [
        "34-aarch64",
        "34",
        "latest",
        ...
    ],
    "Created": "2022-11-24T13:54:18Z",
    "DockerVersion": "1.10.1",
    "Labels": {
        "license": "MIT",
        "name": "fedora",
        "vendor": "Fedora Project",
        "version": "37"
    },
    "Architecture": "amd64",
    "Os": "linux",
    "Layers": [
        "sha256:2a0fc6bf62e155737f0ace6142ee686f3c471c1aab4241dc3128904db46288f0"
    ],
    "LayersData": [
        {
            "MIMEType": "application/vnd.docker.image.rootfs.diff.tar.gzip",
            "Digest": "sha256:2a0fc6bf62e155737f0ace6142ee686f3c471c1aab4241dc3128904db46288f0",
            "Size": 71355009,
            "Annotations": null
        }
    ],
    "Env": [
        "DISTTAG=f37container",
        "FGC=f37",
        "container=oci"
    ]
}

Show container configuration from fedora:latest

$ skopeo inspect --config docker://registry.fedoraproject.org/fedora:latest  | jq
{
  "created": "2020-04-29T06:48:16Z",
  "architecture": "amd64",
  "os": "linux",
  "config": {
    "Env": [
      "DISTTAG=f32container",
      "FGC=f32",
      "container=oci"
    ],
    "Cmd": [
      "/bin/bash"
    ],
    "Labels": {
      "license": "MIT",
      "name": "fedora",
      "vendor": "Fedora Project",
      "version": "32"
    }
  },
  "rootfs": {
    "type": "layers",
    "diff_ids": [
      "sha256:a4c0fa2b217d3fd63d51e55a6fd59432e543d499c0df2b1acd48fbe424f2ddd1"
    ]
  },
  "history": [
    {
      "created": "2020-04-29T06:48:16Z",
      "comment": "Created by Image Factory"
    }
  ]
}

Show unverified image’s digest

$ skopeo inspect docker://registry.fedoraproject.org/fedora:latest | jq '.Digest'
"sha256:655721ff613ee766a4126cb5e0d5ae81598e1b0c3bcf7017c36c4d72cb092fe9"

Copying images

skopeo can copy container images between various storage mechanisms, including:

• Container registries

  • The Quay, Docker Hub, OpenShift, GCR, Artifactory …

• Container Storage backends

  • github.com/containers/storage (Backend for Podman, CRI-O, Buildah and friends)

  • Docker daemon storage

• Local directories

• Local OCI-layout directories

$ skopeo copy docker://quay.io/buildah/stable docker://registry.internal.company.com/buildah
$ skopeo copy oci:busybox_ocilayout:latest dir:existingemptydirectory

Deleting images

$ skopeo delete docker://localhost:5000/imagename:latest

Syncing registries

$ skopeo sync --src docker --dest dir registry.example.com/busybox /media/usb