Ignorant hack of a script to mirror multiarch images on Docker Hub. Requires docker and jq.

mirror-image.sh

#!/bin/bash

FLAGS=""
SOURCE="docker.io/library"
DEST="docker.io/brandond"
IMAGE="busybox"
TAG="1.32.0-uclibc"

docker buildx imagetools inspect ${SOURCE}/${IMAGE}:${TAG} --raw | \
  jq -r '.manifests[] | (.digest + " " + .platform.architecture)' | \
  while read DIGEST ARCH; do
    docker pull ${SOURCE}/${IMAGE}:${TAG}@${DIGEST}
    docker tag ${SOURCE}/${IMAGE}:${TAG}@${DIGEST} ${DEST}/${IMAGE}:${TAG}-${ARCH}
    docker push ${DEST}/${IMAGE}:${TAG}-${ARCH}
    docker buildx imagetools create ${FLAGS} --tag ${DEST}/${IMAGE}:${TAG} ${DEST}/${IMAGE}:${TAG}-${ARCH};
    docker buildx imagetools create ${FLAGS} --tag ${DEST}/${IMAGE}:latest ${DEST}/${IMAGE}:${TAG}-${ARCH};
    FLAGS="--append"
done