CLAUDE.md

Docker Build Platform Notes

Building for Multiple Platforms

When building Docker images, it's important to consider the target platform architecture.

Default Platform in Makefile

The Makefile currently defaults to linux/amd64:

DOCKER_PLATFORM?=linux/amd64

Building for ARM64 (Apple Silicon)

If you're on an ARM64 system (Apple Silicon Macs), you should override the platform:

make build-node24 DOCKER_PLATFORM=linux/arm64

Or export it as an environment variable:

export DOCKER_PLATFORM=linux/arm64
make build-node24

Building for AMD64 (Intel/x86_64)

For Intel-based systems or when building for AMD64 servers:

make build-node24 DOCKER_PLATFORM=linux/amd64

Building for Both Platforms

To build multi-platform images (for pushing to Docker Hub):

docker buildx build \
  --platform linux/amd64,linux/arm64 \
  --pull \
  --push \
  -t dockette/ci:node24 \
  ./node24

Note: Multi-platform builds with --push require pushing to a registry. For local builds, use --load with a single platform.

Quick Local Build

For quick local testing, you can use --load with your native platform:

# Detects your platform automatically
docker buildx build --load -t dockette/ci:node24 ./node24

Platform Detection

To check your current platform:

uname -m  # arm64 or x86_64
docker version --format '{{.Server.Arch}}'  # aarch64 or x86_64