how to set architecture when building multi-arch Docker image?

Question

Let's say I have an app foo built for many different arches (e.g, foo-arm64, foo-amd64, etc). I would like to make very small Docker images like so:

FROM scratch

ARG ARCH
ADD foo-$ARCH /bin/foo

ENTRYPOINT [ "/bin/foo" ]

However, when I build an image:

docker build -t foo:arm64 --platform linux/arm64 --build-arg ARCH=arm64 .

the architecture isn't correct:

docker inspect foo:arm64 | grep Arch
        "Architecture": "amd64",              # should be arm64??

The image arch seems to always come from the host. How can I build a Docker image with the right architecture when that differs from the host? How do the official Docker images do this?

I'm running the build on an `amd64` server and am trying to create images for `amd64`, `arm64v8`, `arm32v7`, and `ppc64le` — paleozogt, Mar 17 '20 at 18:28

score 2 · Answer 1 · answered Mar 19 '20 at 07:03

2

Use docker buildx command instead of docker build -t command. Docker build only create docker image with respective platform.

For more information refer documentation : https://www.docker.com/blog/multi-arch-images/

answered Mar 19 '20 at 07:03

snehal

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how to set architecture when building multi-arch Docker image?

1 Answers1