fix CI timeout issue with multi arch builds (kubernetes-sigs#2572)

Author: farazmd

Dockerfile

@@ -4,10 +4,11 @@ ARG BUILDER_IMAGE=golang:1.25
 ARG BASE_IMAGE=gcr.io/distroless/static:nonroot
 
 ## Multistage build
-FROM ${BUILDER_IMAGE} AS builder
+FROM --platform=${BUILDPLATFORM} ${BUILDER_IMAGE} AS builder
+ARG TARGETARCH
 ENV CGO_ENABLED=0
 ENV GOOS=linux
-ENV GOARCH=amd64
+ENV GOARCH=${TARGETARCH}
 ARG COMMIT_SHA=unknown
 ARG BUILD_REF
 

bbr.Dockerfile

@@ -4,10 +4,11 @@ ARG BUILDER_IMAGE=golang:1.25
 ARG BASE_IMAGE=gcr.io/distroless/static:nonroot
 
 ## Multistage build
-FROM ${BUILDER_IMAGE} AS builder
+FROM --platform=${BUILDPLATFORM} ${BUILDER_IMAGE} AS builder
+ARG TARGETARCH
 ENV CGO_ENABLED=0
 ENV GOOS=linux
-ENV GOARCH=amd64
+ENV GOARCH=${TARGETARCH}
 ARG COMMIT_SHA=unknown
 ARG BUILD_REF
 

cloudbuild.yaml

@@ -13,6 +13,7 @@ steps:
     - EXTRA_TAG=$_PULL_BASE_REF
     - DOCKER_BUILDX_CMD=/buildx-entrypoint
     - GIT_COMMIT_SHA=$_PULL_BASE_SHA
+    - PLATFORMS=linux/amd64,linux/arm64
   - name: gcr.io/k8s-staging-test-infra/gcb-docker-gcloud:v20240718-5ef92b5c36
     entrypoint: make
     args:
@@ -21,6 +22,7 @@ steps:
     - GIT_TAG=$_GIT_TAG
     - EXTRA_TAG=$_PULL_BASE_REF
     - DOCKER_BUILDX_CMD=/buildx-entrypoint
+    - PLATFORMS=linux/amd64,linux/arm64
   - name: gcr.io/k8s-staging-test-infra/gcb-docker-gcloud:v20240718-5ef92b5c36
     entrypoint: make
     args:
@@ -38,6 +40,7 @@ steps:
     - GIT_TAG=$_GIT_TAG
     - EXTRA_TAG=$_PULL_BASE_REF
     - DOCKER_BUILDX_CMD=/buildx-entrypoint
+    - PLATFORMS=linux/amd64,linux/arm64
   - name: gcr.io/k8s-staging-test-infra/gcb-docker-gcloud:v20240718-5ef92b5c36
     entrypoint: make
     args:
@@ -48,6 +51,7 @@ steps:
     - GIT_TAG=$_GIT_TAG
     - EXTRA_TAG=$_PULL_BASE_REF
     - DOCKER_BUILDX_CMD=/buildx-entrypoint
+    - PLATFORMS=linux/amd64,linux/arm64
 substitutions:
   # _GIT_TAG will be filled with a git-based tag for the image, of the form vYYYYMMDD-hash, and
   # can be used as a substitution