Multi-arch manifest using "application/vnd.docker.container.image.combined+json"

gistfile1.json

{
    "schemaVersion": 2,
    "target": {
        "mediaType": "application/vnd.docker.container.image.v1+json",
        "length": 7023,
        "digest": "sha256:b5b2b2c507a0944348e0303114d8d93aaaa081732b86451d9bce1f432a537bc7"
    },
    "dependencies": [
        
        {
            "mediaType": "application/vnd.docker.container.image.combined+json",
	    "linux":  {
                  "amd64": [{
                      "mediaType": "application/vnd.docker.container.image.rootfs.diff+x-tar",
                      "length": 16724,
                      "digest": "sha256:3c3a4604a545cdc127456d94e421cd355bca5b528f4a9c1905b15da2eb4a4c6b"
                      },
			{
                      "mediaType": "application/vnd.docker.container.image.rootfs.diff+x-tar",
                      "length": 16724,
                      "digest": "sha256:3c3a4604a545cdc127456d94e421cd355bca5b528f4a9c1905b15da2eb4a4c6b"
                      }
                   ],
                  "arm": [{
                      "mediaType": "application/vnd.docker.container.image.rootfs.diff+x-tar",
                      "length": 16724,
                      "digest": "sha256:3c3a4604a545cdc127456d94e421cd355bca5b528f4a9c1905b15da2eb4a4c6b"
                      },
			{
                      "mediaType": "application/vnd.docker.container.image.rootfs.diff+x-tar",
                      "length": 16724,
                      "digest": "sha256:3c3a4604a545cdc127456d94e421cd355bca5b528f4a9c1905b15da2eb4a4c6b"
                      }
                   ],
                  "ppc64le": [{
                      "mediaType": "application/vnd.docker.container.image.rootfs.diff+x-tar",
                      "length": 16724,
                      "digest": "sha256:3c3a4604a545cdc127456d94e421cd355bca5b528f4a9c1905b15da2eb4a4c6b"
                      },
			{
                      "mediaType": "application/vnd.docker.container.image.rootfs.diff+x-tar",
                      "length": 16724,
                      "digest": "sha256:3c3a4604a545cdc127456d94e421cd355bca5b528f4a9c1905b15da2eb4a4c6b"
                      }
                   ]
            }
        }, 
        {
            "mediaType": "application/vnd.docker.container.image.combined+json",
	    "windows":  {
                  "amd64": [{
                      "mediaType": "application/vnd.docker.container.image.rootfs.diff+x-tar",
                      "length": 16724,
                      "digest": "sha256:3c3a4604a545cdc127456d94e421cd355bca5b528f4a9c1905b15da2eb4a4c6b"
                      },
			{
                      "mediaType": "application/vnd.docker.container.image.rootfs.diff+x-tar",
                      "length": 16724,
                      "digest": "sha256:3c3a4604a545cdc127456d94e421cd355bca5b528f4a9c1905b15da2eb4a4c6b"
                      }
                   ],
                  "arm": [{
                      "mediaType": "application/vnd.docker.container.image.rootfs.diff+x-tar",
                      "length": 16724,
                      "digest": "sha256:3c3a4604a545cdc127456d94e421cd355bca5b528f4a9c1905b15da2eb4a4c6b"
                      },
			{
                      "mediaType": "application/vnd.docker.container.image.rootfs.diff+x-tar",
                      "length": 16724,
                      "digest": "sha256:3c3a4604a545cdc127456d94e421cd355bca5b528f4a9c1905b15da2eb4a4c6b"
                      }
                   ],
                  "ppc64le": [{
                      "mediaType": "application/vnd.docker.container.image.rootfs.diff+x-tar",
                      "length": 16724,
                      "digest": "sha256:3c3a4604a545cdc127456d94e421cd355bca5b528f4a9c1905b15da2eb4a4c6b"
                      },
			{
                      "mediaType": "application/vnd.docker.container.image.rootfs.diff+x-tar",
                      "length": 16724,
                      "digest": "sha256:3c3a4604a545cdc127456d94e421cd355bca5b528f4a9c1905b15da2eb4a4c6b"
                      }
                   ]
            }
        }
    ],
    "labels": {
        "createdAt": "2015-06-16T16:29:07.952493971-07:00",
        "version": "3.1.4-a159+265"
    }
}

@harche This is not really the right approach. It ruins the generality of the manifest. The manifest knows nothing about operating systems or architectures. It is a distribution structure and decoupled from docker. This leaves control in docker engine's hands and keeps this stuff out of registry code.

Checkout my comments here:

distribution/distribution#62 (comment)

This defines "alternates", that can be labelled. This will provide a solid, backwards compatible approach. It is also efficient for the vast majority of users who only use linux-amd64. The target could be labelled, as well, so the primary target could be changed in the future.