Add multiarch building support

Signed-off-by: Bin Lu <bin.lu@arm.com>

Dockerfile

@@ -1,5 +1,7 @@
 # Build node feature discovery
-FROM golang:1.8 as builder
+FROM BASEIMAGE1 as builder
+
+CROSS_BUILD_COPY qemu-QEMUARCH-static /usr/bin/
 
 ADD . /go/src/sigs.k8s.io/node-feature-discovery
 
@@ -32,12 +34,16 @@ RUN go test .
 
 
 # Create production image for running node feature discovery
-FROM debian:stretch-slim
+FROM BASEIMAGE2
+
+CROSS_BUILD_COPY qemu-QEMUARCH-static /usr/bin/
 
 COPY --from=builder /usr/local/bin /usr/local/bin
 COPY --from=builder /usr/local/lib /usr/local/lib
 COPY --from=builder /etc/kubernetes/node-feature-discovery /etc/kubernetes/node-feature-discovery
 RUN ldconfig
 COPY --from=builder /go/bin/node-feature-discovery /usr/bin/node-feature-discovery
 
+RUN rm /usr/bin/qemu-*-static -f
+
 ENTRYPOINT ["/usr/bin/node-feature-discovery"]

Makefile

@@ -1,3 +1,8 @@
+ARCH?=amd64
+ALL_ARCH = amd64 arm arm64 ppc64le s390x
+
+QEMUVERSION=v2.9.1
+
 .PHONY: all
 
 IMAGE_BUILD_CMD := docker build
@@ -8,10 +13,73 @@ DOCKER_IMAGE_NAME := node-feature-discovery
 
 VERSION := $(shell git describe --tags --dirty --always)
 
+ifeq ($(ARCH),amd64)
+	BASEIMAGE1?=golang:1.11-stretch
+	BASEIMAGE2?=debian:stretch-slim
+endif
+ifeq ($(ARCH),arm)
+	BASEIMAGE1?=arm32v7/golang:1.11-stretch
+	BASEIMAGE2?=arm32v7/debian:stretch-slim
+	QEMUARCH=arm
+endif
+ifeq ($(ARCH),arm64)
+	BASEIMAGE1?=arm64v8/golang:1.11-stretch
+	BASEIMAGE2?=arm64v8/debian:stretch-slim
+	QEMUARCH=aarch64
+endif
+ifeq ($(ARCH),ppc64le)
+	BASEIMAGE1?=ppc64le/golang:1.11-stretch
+	BASEIMAGE2?=ppc64le/debian:stretch-slim
+	QEMUARCH=ppc64le
+endif
+ifeq ($(ARCH),s390x)
+	BASEIMAGE1?=s390x/golang:1.11-stretch
+	BASEIMAGE2?=s390x/debian:stretch-slim
+	QEMUARCH=s390x
+endif
+
+check-docker:
+	@if [ -z $$(which docker) ]; then \
+          echo "Missing \`docker\` client which is required for development"; \
+          exit 2; \
+        fi
+
 all: image
 
 # To override QUAY_REGISTRY_USER use the -e option as follows:
 # QUAY_REGISTRY_USER=<my-username> make docker -e.
-image:
+image: check-docker
+	cat Dockerfile \
+		| sed "s|BASEIMAGE1|$(BASEIMAGE1)|g" \
+		| sed "s|BASEIMAGE2|$(BASEIMAGE2)|g" \
+		| sed "s|QEMUARCH|$(QEMUARCH)|g" \
+		> Dockerfile.build
+
+ifeq ($(ARCH),amd64)
+        # When building "normally" for amd64, remove the whole line, it has no part in the amd64 image
+	sed "/CROSS_BUILD_/d" Dockerfile.build > Dockerfile.build.tmp
+else
+        # When cross-building, only the placeholder "CROSS_BUILD_" should be removed
+        # Register /usr/bin/qemu-ARCH-static as the handler for non-x86 binaries in the kernel
+	docker run --rm --privileged multiarch/qemu-user-static:register --reset
+	curl -sSL https://github.com/multiarch/qemu-user-static/releases/download/$(QEMUVERSION)/x86_64_qemu-$(QEMUARCH)-static.tar.gz | tar -xz -C ./ 
+        # Ensure we don't get surprised by umask settings
+	chmod 0755 qemu-$(QEMUARCH)-static
+	sed "s/CROSS_BUILD_//g" Dockerfile.build > Dockerfile.build.tmp
+endif
+
+ifeq ($(ARCH),amd64)
+	$(IMAGE_BUILD_CMD) --build-arg NFD_VERSION=$(VERSION) \
+		-t $(QUAY_DOMAIN_NAME)/$(QUAY_REGISTRY_USER)/$(DOCKER_IMAGE_NAME):$(VERSION) -f Dockerfile.build.tmp ./
+endif
 	$(IMAGE_BUILD_CMD) --build-arg NFD_VERSION=$(VERSION) \
-		-t $(QUAY_DOMAIN_NAME)/$(QUAY_REGISTRY_USER)/$(DOCKER_IMAGE_NAME):$(VERSION) ./
+		-t $(QUAY_DOMAIN_NAME)/$(QUAY_REGISTRY_USER)/$(DOCKER_IMAGE_NAME)-$(ARCH):$(VERSION) -f Dockerfile.build.tmp ./
+
+	rm Dockerfile.build* -f
+	rm qemu-*-static -f
+
+# Building multi-arch docker images
+images-all: check-docker
+	for arch in $(ALL_ARCH); do \
+		$(MAKE) image ARCH=$$arch; \
+	done