images/alpine: Build for arm64

[LorbusChris]

This commit adds a Google Cloud Build definition for building alpine
arm64 images and pushing them as a manifest list together with their
amd64 counterparts.

This is a prereq for #16588 and #22362

Blocked on: #22599

/cc @stevekuznetsov

[k8s-ci-robot]

Hi @LorbusChris. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[petr-muller]

/ok-to-test

[LorbusChris]

/cc @BenTheElder

[LorbusChris]

looking at the file history, @fejta might be best suited for a review of these changes.
/cc @fejta
/uncc @BenTheElder

[spiffxp]

/cc
I'm going to guess this will fail in the same way as #22450 (comment)

EDIT: yeah, it fails

Starting Step #1
Step #1: Already have image (with digest): gcr.io/cloud-builders/docker
Step #1: Sending build context to Docker daemon  5.632kB
Step #1: Step 1/4 : FROM alpine:latest
Step #1:  ---> 6dbb9cc54074
Step #1: Step 2/4 : ARG IMAGE_ARG
Step #1:  ---> Using cache
Step #1:  ---> 8721f6f4cec6
Step #1: Step 3/4 : ENV IMAGE=${IMAGE_ARG}
Step #1:  ---> Running in c37512c3b071
Step #1: Removing intermediate container c37512c3b071
Step #1:  ---> 147b6460c43f
Step #1: Step 4/4 : RUN apk add --no-cache ca-certificates && update-ca-certificates
Step #1:  ---> Running in 7e63302ac69c
Step #1: fetch https://dl-cdn.alpinelinux.org/alpine/v3.13/main/x86_64/APKINDEX.tar.gz
Step #1: fetch https://dl-cdn.alpinelinux.org/alpine/v3.13/community/x86_64/APKINDEX.tar.gz
Step #1: (1/1) Installing ca-certificates (20191127-r5)
Step #1: Executing busybox-1.32.1-r6.trigger
Step #1: Executing ca-certificates-20191127-r5.trigger
Step #1: OK: 6 MiB in 15 packages
Step #1: WARNING: ca-certificates.crt does not contain exactly one certificate or CRL: skipping
Step #1: Removing intermediate container 7e63302ac69c
Step #1:  ---> c75db636ff48
Step #1: [Warning] One or more build-args [ARCH] were not consumed
Step #1: Successfully built c75db636ff48
Step #1: Successfully tagged gcr.io/k8s-staging-test-infra/alpine:v20210610-54b097ac3e-arm64
Finished Step #1
Starting Step #2
Step #2: Already have image (with digest): gcr.io/cloud-builders/docker
Step #2: no such manifest: gcr.io/k8s-staging-test-infra/alpine:v20210610-54b097ac3e
Finished Step #2
ERROR
ERROR: build step 2 "gcr.io/cloud-builders/docker" failed: step exited with non-zero status: 1

[LorbusChris]

#22599 has landed. This PR should be ready now.

[fejta]

What is the reason for dropping these? (or rather moving pushing them into the build step)
https://cloud.google.com/build/docs/build-config#images

[LorbusChris]

This doesn't seem to work with manifest lists.
Using:

steps:
  - name: gcr.io/k8s-testimages/gcb-docker-gcloud
    entrypoint: /buildx-entrypoint
    args:
    - build
    - --tag=gcr.io/$PROJECT_ID/alpine:$_GIT_TAG
    - --tag=gcr.io/$PROJECT_ID/alpine:latest
    - --platform=linux/amd64,linux/arm64/v8
    - --build-arg=IMAGE_ARG=gcr.io/$PROJECT_ID/alpine:$_GIT_TAG
    - .
    dir: .
substitutions:
  _GIT_TAG: '12345'
images:
  - 'gcr.io/$PROJECT_ID/alpine:$_GIT_TAG'
  - 'gcr.io/$PROJECT_ID/alpine:latest'

yields:

ERROR: failed to find one or more images after execution of build steps: ["gcr.io/k8s-staging-test-infra/alpine:v20210618-1bc5e9d8bf" "gcr.io/k8s-staging-test-infra/alpine:latest"]

[BenTheElder]

GCR specific but cheap and simple gcloud container images add-tag.

To do it generically you'd need to push the manifest again as a tag (and only the manifest, the underlying resources should already be pushed), crane can do this (and other super useful things!) see: crane tag

[LorbusChris]

/hold
using the --tag flag twice in one command doesn't seem to work and will actually only tag the latter

[LorbusChris]

Thanks @BenTheElder, let's go the easy way with gcloud as that's in the image already.
Should be fixed now.
/hold cancel

[BenTheElder]

lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: BenTheElder, LorbusChris

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[LorbusChris]

@BenTheElder it looks like this broke the postsubmit job https://prow.k8s.io/view/gs/kubernetes-jenkins/logs/post-test-infra-push-alpine/1405964567472771072

[LorbusChris]

#22609