Build docker image for both arm64 and amd64 in macbook m1

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Problem

You are using macbook with m1 chip, and you want to build docker image that can run under both arm64 and amd64.

If you don’t do any special config, when you build an image in your macbook m1, then pull the image and run in Linux/amd64, it may fail to run or raise a warning message:

WARNING: The requested image’s platform (linux/arm64/v8) does not match the detected host platform (linux/amd64) and no specific platform was requested

If it just raises this warning message, then put the parameter --platform could solve it:

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# when run an arm64 image in linux/amd64
$ docker run --rm -p 3000:3000 --platform linux/arm64/v8 yourimage:1.0.0

Another solution is, when build an image in your macbook m1, always use a amd64 image, for example, if you are using FROM alpine:3.14, change it to FROM amd64/alpine:3.14, then you will get an image that can run under amd64, which means when you run it in your linux, it won’t raise any error. But when you run it directly in your macbook m1, it will raise a similar warning like above, and this time you need to specify the platform argument to linux/amd64:

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# when run an amd64 image in macbook m1 (arm64)
$ docker run --rm -p 3000:3000 --platform linux/amd64 yourimage:1.0.0

The third solution is, when build your image, make it runnable on both arm64 and amd64 by default:

Solution

Steps:

  1. Open your file ~/.docker/config.json, change the field experimental from disabled to enabled

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    {
      //...
      "experimental" : "enabled"
    }

  2. Restart your “Docker Desktop for Mac”

  3. Run docker buildx create --use, this will generate a builder that let you specify multilple docker platforms at once.

  4. Run docker buildx build --platform linux/amd64,linux/arm64 --push -t <tag_to_push> ., this will generate 2 images and push it to your docker registry. PLEASE NOTICE, here you have to specify the --push and push it to your registry, for example:

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    $ docker buildx build --platform linux/amd64,linux/arm64 --push -t registry.gitlab.com/myaccount/mydockerregistry/helloworld:1.0.0 .

  5. All set, you can now run docker run <tag> on both macbook with m1 and on your linux server. It will first pull the image from your registry based on your CPU’s arch, then run it. Since the image it pulled based on the CPU arch, you won’t have any warning message on either platform.

Please notice that you need to push your image to the remote registry at the build stage, if you are still in the stage of building and testing your image, you probably don’t want to use this special build method. In the building and testing your image stage, it is better you uses the normal docker build command, and once it is done, run the docker buildx build --platform to build a your release and push to the remote registery.

Reference: