docker buildx for multiarch support

create a builder

Newer Docker (Docker Desktop / Engine 29.0+ with the containerd image store) can build multi-platform images with the default docker builder. On older setups the default builder still rejects --platform, so create a docker-container builder like this — it is also required when you use a custom buildkitd.toml or push straight to a registry:

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docker buildx create  --use --name multiarch --driver docker-container

if your self-build registry is not https, please touch a buildkitd.toml

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[registry."your-registry-domain or ip"]
http = true
insecure = true

Note: http = true is for plain-HTTP registries; insecure = true is for HTTPS with a self-signed certificate (usually pick one, not both).

and then use this config to create a builder

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# if your builder has already existed, delete it and create
docker buildx rm multiarch
docker buildx create  --use --name multiarch --driver docker-container --config ./buildkitd.toml

build the multiarch image and push it to your registry

Make sure you are logged in to the target registry first (pushing images requires authentication):

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docker login your-registry-domain or ip

docker buildx inspect --bootstrap to get the supported platform information

On Linux, if you build for a platform you don’t have natively (e.g. arm64 on an amd64 host), register the emulator first — QEMU/binfmt is bundled with Docker Desktop, but manual setups need:

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docker run --privileged --rm tonistiigi/binfmt --install all

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# don't ignore the trailing dot, it's to search the current directory's Dockerfile file
docker buildx build --push --platform linux/amd64,linux/arm64 -t pplmx/demo:v2.0.0 .

# if you wanna to specify a Dockerfile
docker buildx build --push --platform linux/amd64,linux/arm64 -t pplmx/demo:v2.0.0 -f ./Dockerfile