Optimize multi-arch docker image build

Author: maxsxu

Dockerfile

@@ -1,5 +1,5 @@
 # Build the manager binary
-FROM golang:1.25.8-trixie AS builder
+FROM --platform=$BUILDPLATFORM golang:1.25.8-trixie as builder
 
 WORKDIR /workspace/api
 COPY api/ .
@@ -20,11 +20,13 @@ COPY controllers/ controllers/
 COPY utils/ utils/
 
 # Build
-RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 GO111MODULE=on go build -a -o manager main.go
+ARG TARGETOS
+ARG TARGETARCH
+RUN CGO_ENABLED=0 GOOS=${TARGETOS:-linux} GOARCH=${TARGETARCH:-amd64} GO111MODULE=on go build -a -o manager main.go
 
 # Use distroless as minimal base image to package the manager binary
 # Refer to https://github.com/GoogleContainerTools/distroless for more details
-FROM gcr.io/distroless/static:nonroot
+FROM --platform=$TARGETPLATFORM gcr.io/distroless/static:nonroot
 WORKDIR /
 COPY --from=builder /workspace/manager .
 USER 65532:65532

operator.Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine:3.21
+FROM --platform=$TARGETPLATFORM alpine:3.21
 
 ENV GID=10001
 ENV UID=10000

redhat.Dockerfile

@@ -1,5 +1,5 @@
 # Build the manager binary
-FROM golang:1.25.8-trixie as builder
+FROM --platform=$BUILDPLATFORM golang:1.25.8-trixie AS builder
 
 WORKDIR /workspace/api
 COPY api/ .
@@ -20,12 +20,14 @@ COPY controllers/ controllers/
 COPY utils/ utils/
 
 # Build
-RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 GO111MODULE=on go build -a -o manager main.go
+ARG TARGETOS
+ARG TARGETARCH
+RUN CGO_ENABLED=0 GOOS=${TARGETOS:-linux} GOARCH=${TARGETARCH:-amd64} GO111MODULE=on go build -a -o manager main.go
 
 # Use ubi image as the base image which is required by the red hat certification.
 # Base on the image size, the order is ubi > ubi-minimal > ubi-micro.
 # https://access.redhat.com/documentation/en-us/red_hat_software_certification/8.45/html/red_hat_openshift_software_certification_policy_guide/assembly-requirements-for-container-images_openshift-sw-cert-policy-introduction#con-image-metadata-requirements_openshift-sw-cert-policy-container-images
-FROM registry.access.redhat.com/ubi8/ubi-micro:latest
+FROM --platform=$TARGETPLATFORM registry.access.redhat.com/ubi8/ubi-micro:latest
 
 ARG VERSION