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OCI Image Manifest List Specification

The manifest list is a higher-level manifest which points to specific image manifests for one or more platforms. While the use of a manifest list is OPTIONAL for image providers, image consumers SHOULD be prepared to process them.

This section defines the application/vnd.oci.image.manifest.list.v1+json media type. For the media type(s) that this document is compatible with, see the matrix.

Manifest List Property Descriptions

  • schemaVersion int

    This REQUIRED property specifies the image manifest schema version. For this version of the specification, this MUST be 2 to ensure backward compatibility with older versions of Docker. The value of this field will not change. This field MAY be removed in a future version of the specification.

  • mediaType string

    This property is reserved for use, to maintain compatibility. When used, this field contains the media type of this document, which differs from the descriptor use of mediaType.

  • manifests array of objects

    This REQUIRED property contains a list of manifests for specific platforms. While the property MUST be present, the size of the array MAY be zero.

    Each object in manifests is a descriptor with the following additional properties and restrictions:

    • mediaType string

      This descriptor property has additional restrictions for manifests. Implementations MUST support at least the following media types:

      Manifest lists concerned with portability SHOULD use one of the above media types.

    • platform object

      This REQUIRED property describes the platform which the image in the manifest runs on.

      • architecture string

        This REQUIRED property specifies the CPU architecture. Manifest lists SHOULD use, and implementations SHOULD understand, values supported by runtime-spec's platform.arch.

      • os string

        This REQUIRED property specifies the operating system. Manifest lists SHOULD use, and implementations SHOULD understand, values supported by runtime-spec's platform.os.

      • os.version string

        This OPTIONAL property specifies the operating system version, for example 10.0.10586.

      • os.features array of strings

        This OPTIONAL property specifies an array of strings, each specifying a mandatory OS feature (for example on Windows win32k).

      • variant string

        This OPTIONAL property specifies the variant of the CPU, for example armv6l to specify a particular CPU variant of the ARM CPU.

      • features array of strings

        This OPTIONAL property specifies an array of strings, each specifying a mandatory CPU feature (for example sse4 or aes).

  • annotations string-string map

    This OPTIONAL property contains arbitrary metadata for the manifest list. Annotations MUST be a key-value map where both the key and value MUST be strings. While the value MUST be present, it MAY be an empty string. Keys MUST be unique within this map, and best practice is to namespace the keys. Keys SHOULD be named using a reverse domain notation - e.g. com.example.myKey. Keys using the org.opencontainers namespace are reserved and MUST NOT be used by other specifications. If there are no annotations then this property MUST either be absent or be an empty map. Implementations that are reading/processing manifest lists MUST NOT generate an error if they encounter an unknown annotation key.

    See Pre-Defined Annotation Keys.

Extensibility

Implementations that are reading/processing manifest lists MUST NOT generate an error if they encounter an unknown property. Instead they MUST ignore unknown properties.

Example Manifest List

Example showing a simple manifest list pointing to image manifests for two platforms:

{
  "schemaVersion": 2,
  "mediaType": "application/vnd.oci.image.manifest.list.v1+json",
  "manifests": [
    {
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "size": 7143,
      "digest": "sha256:e692418e4cbaf90ca69d05a66403747baa33ee08806650b51fab815ad7fc331f",
      "platform": {
        "architecture": "ppc64le",
        "os": "linux"
      }
    },
    {
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "size": 7682,
      "digest": "sha256:5b0bcabd1ed22e9fb1310cf6c2dec7cdef19f0ad69efa1f392e94a4333501270",
      "platform": {
        "architecture": "amd64",
        "os": "linux",
        "os.features": [
          "sse4"
        ]
      }
    }
  ],
  "annotations": {
    "com.example.key1": "value1",
    "com.example.key2": "value2"
  }
}