From bf91e6790e90a00193aeffa0962a1ed2f63abad4 Mon Sep 17 00:00:00 2001
From: Sean Malloy <sean.malloy@kohls.com>
Date: Thu, 3 Dec 2020 00:06:22 -0600
Subject: [PATCH 1/2] Enable Multi-Arch Container Image Builds

Previous to this change official descheduler container images only
supported the AMD64 hardware architecture. This change enables
building official descheduler container images for multiple
architectures.

The initially supported architectures are AMD64 and ARM64.
---
 Dockerfile      |  3 ++-
 Makefile        | 29 ++++++++++++++++++++++++++---
 cloudbuild.yaml |  2 +-
 3 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 0208b970b..b3dfc3879 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -15,8 +15,9 @@ FROM golang:1.15.2
 
 WORKDIR /go/src/sigs.k8s.io/descheduler
 COPY . .
+ARG ARCH
 ARG VERSION
-RUN VERSION=${VERSION} make
+RUN VERSION=${VERSION} make build.$ARCH
 
 FROM scratch
 
diff --git a/Makefile b/Makefile
index f74f26c00..b05a62e9e 100644
--- a/Makefile
+++ b/Makefile
@@ -18,6 +18,7 @@
 VERSION?=v$(shell date +%Y%m%d)-$(shell git describe --tags --match "v*")
 BUILD=$(shell date +%FT%T%z)
 LDFLAG_LOCATION=sigs.k8s.io/descheduler/cmd/descheduler/app
+ARCHS = amd64 arm64
 
 LDFLAGS=-ldflags "-X ${LDFLAG_LOCATION}.version=${VERSION} -X ${LDFLAG_LOCATION}.buildDate=${BUILD}"
 
@@ -47,18 +48,40 @@ all: build
 build:
 	CGO_ENABLED=0 go build ${LDFLAGS} -o _output/bin/descheduler sigs.k8s.io/descheduler/cmd/descheduler
 
+build.amd64:
+	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build ${LDFLAGS} -o _output/bin/descheduler sigs.k8s.io/descheduler/cmd/descheduler
+
+build.arm64:
+	CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build ${LDFLAGS} -o _output/bin/descheduler sigs.k8s.io/descheduler/cmd/descheduler
+
 dev-image: build
 	docker build -f Dockerfile.dev -t $(IMAGE) .
 
 image:
-	docker build --build-arg VERSION="$(VERSION)" -t $(IMAGE) .
+	docker build --build-arg VERSION="$(VERSION)" --build-arg ARCH="amd64" -t $(IMAGE) .
 
-push-container-to-gcloud: image
+image.amd64:
+	docker build --build-arg VERSION="$(VERSION)" --build-arg ARCH="amd64" -t $(IMAGE)-amd64 .
+
+image.arm64:
+	docker build --build-arg VERSION="$(VERSION)" --build-arg ARCH="arm64" -t $(IMAGE)-arm64 .
+
+push: image
 	gcloud auth configure-docker
 	docker tag $(IMAGE) $(IMAGE_GCLOUD)
 	docker push $(IMAGE_GCLOUD)
 
-push: push-container-to-gcloud
+push-all: image.amd64 image.arm64
+	gcloud auth configure-docker
+	for arch in $(ARCHS); do \
+		docker tag $(IMAGE)-$${arch} $(IMAGE_GCLOUD)-$${arch} ;\
+		docker push $(IMAGE_GCLOUD)-$${arch} ;\
+	done
+	DOCKER_CLI_EXPERIMENTAL=enabled docker manifest create $(IMAGE_GCLOUD) $(addprefix --amend $(IMAGE_GCLOUD)-, $(ARCHS))
+	for arch in $(ARCHS); do \
+		DOCKER_CLI_EXPERIMENTAL=enabled docker manifest annotate --arch $${arch} $(IMAGE_GCLOUD) $(IMAGE_GCLOUD)-$${arch} ;\
+	done
+	DOCKER_CLI_EXPERIMENTAL=enabled docker manifest push $(IMAGE_GCLOUD) ;\
 
 clean:
 	rm -rf _output
diff --git a/cloudbuild.yaml b/cloudbuild.yaml
index d9a9b5605..a80de306e 100644
--- a/cloudbuild.yaml
+++ b/cloudbuild.yaml
@@ -14,7 +14,7 @@ steps:
     - VERSION=$_GIT_TAG
     - BASE_REF=$_PULL_BASE_REF
     args:
-    - push
+    - push-all
 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

From 94f1c7dd8d4309b0886047b2d6491e1b7e43d60d Mon Sep 17 00:00:00 2001
From: Sean Malloy <sean.malloy@kohls.com>
Date: Thu, 3 Dec 2020 00:44:19 -0600
Subject: [PATCH 2/2] Document Multi-Arch Container Image Usage

---
 docs/release-guide.md |  2 +-
 docs/user-guide.md    | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/docs/release-guide.md b/docs/release-guide.md
index 9a0adeb14..d780a772e 100644
--- a/docs/release-guide.md
+++ b/docs/release-guide.md
@@ -20,7 +20,7 @@
 3. Push the release branch to the descheuler repo and ensure branch protection is enabled (not required for patch releases)
 4. Tag the repository from the `master` branch (from the `release-1.18` branch for a patch release) and push the tag `VERSION=v0.18.0 git tag -m $VERSION $VERSION; git push origin $VERSION`
 5. Checkout the tag you just created and make sure your repo is clean by git's standards `git checkout $VERSION`
-6. Build and push the container image to the staging registry `VERSION=$VERSION make push`
+6. Build and push the container image to the staging registry `VERSION=$VERSION make push-all`
 7. Publish a draft release using the tag you just created
 8. Perform the [image promotion process](https://github.com/kubernetes/k8s.io/tree/master/k8s.gcr.io#image-promoter)
 9. Publish release
diff --git a/docs/user-guide.md b/docs/user-guide.md
index 342d75cfe..63a371e25 100644
--- a/docs/user-guide.md
+++ b/docs/user-guide.md
@@ -3,6 +3,16 @@
 Starting with descheduler release v0.10.0 container images are available in the official k8s container registry.
 * `k8s.gcr.io/descheduler/descheduler`
 
+Also, starting with descheduler release v0.20.0 multi-arch container images are provided. Currently AMD64 and ARM64
+container images are provided. Multi-arch container images cannot be pulled by [kind](https://kind.sigs.k8s.io) from
+a registry. Therefore starting with descheduler release v0.20.0 use the below process to download the official descheduler
+image into a kind cluster.
+```
+kind create cluster
+docker pull k8s.gcr.io/descheduler/descheduler:v0.20.0
+kind load docker-image k8s.gcr.io/descheduler/descheduler:v0.20.0
+```
+
 ## Policy Configuration Examples
 The [examples](https://github.com/kubernetes-sigs/descheduler/tree/master/examples) directory has descheduler policy configuration examples.