Multi-Architecture Container Images: Difference between revisions

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* [[Docker_Concepts#Multi-Architecture_Container_Image|Docker Concepts]]
* [[Docker_Concepts#Multi-Architecture_Container_Image|Docker Concepts]]
=Overview=
=Overview=
A container image is represented by a manifest, which is JSON-encoded content representing the image's layers, the corresponding size, the hash of the image, etc. For more details, see: {{Internal|Docker_Concepts#Image|Docker_Concepts | Image}}
A container image is represented by a manifest, which is JSON-encoded content representing the image's layers, the corresponding size, the hash of the image, etc. For more details, see: {{Internal|Docker_Concepts#Image|Docker Concepts | Image}}


This format allows us to put multiple container images, each supporting a different architecture, behind the same tag.  
This format allows us to put multiple container images, each supporting a different architecture, behind the same tag.  
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}
}
</syntaxhighlight>
</syntaxhighlight>
=Building Multi-Architecture Images=
=Building Multi-Architecture Images=



Revision as of 21:47, 20 July 2023

External

Internal

Overview

A container image is represented by a manifest, which is JSON-encoded content representing the image's layers, the corresponding size, the hash of the image, etc. For more details, see:

Docker Concepts | Image

This format allows us to put multiple container images, each supporting a different architecture, behind the same tag.

We can do that with a manifest that contains a list of manifest, so the container engine can pick the one that it matches its runtime. This type of manifest is called a manifest list, and contains a list of different images, one for each architecture.

{
  "mediaType": "application/vnd.docker.distribution.manifest.list.v2+json",
  "schemaVersion": 2,
  "manifests": [
    {
      "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
      "digest": "sha256:5...5",
      "size": 4804,
      "platform": {
        "architecture": "amd64",
        "os": "linux"
      }
    },
    {
      "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
      "digest": "sha256:4...5",
      "size": 4803,
      "platform": {
        "architecture": "arm64",
        "os": "linux"
      }
    }
  ]
}

Building Multi-Architecture Images

The process consists in building and pushing the images for each architecture, then combining them with podman buildx.

podman buildx build --push --platform linux/arm64,linux/amd64 --tag docker.my.org/example/multiarch-example:1.0.0