feat: linux/arm64 compatibility

[isometry]

No description provided.

[kollabpr]

Hi @isometry, Thanks for the feature request and the PR! We will review with the team and get back to you soon.

[dcamzn]

Thank you. We plan to support ARM this year, however, it doesn't look like we can deliver ARM support in Q2.

[isometry]

Thank you. We plan to support ARM this year, however, it doesn't look like we can deliver ARM support in Q2.

What more is needed beyond the changes in this PR? Can we help?

[jtackaberry]

What more is needed beyond the changes in this PR?

I imagine they might want a better integrated solution? Your PR understandably makes efforts to be non-invasive and low risk (by creating a temporary hacked version of the Dockerfile), but IMO a proper solution would just have a working Dockerfile in all cases.

In any case @isometry I tried your patch but the arm64 images aren't actually working on arm64. Classic "exec format error" on execution.

This is because of docker/buildx#510 and I needed to make this change to the Dockerfile to get a proper build:

diff --git a/Dockerfile b/Dockerfile
index 7288a6b..533705f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,8 +2,8 @@
 FROM golang:1.21 as builder
 WORKDIR /workspace

-ARG TARGETARCH=amd64
-ARG TARGETOS=linux
+ARG TARGETARCH
+ARG TARGETOS

 ENV GOPROXY=direct
 # Copy the Go Modules manifests
@@ -18,8 +18,8 @@ COPY main.go main.go
 COPY pkg/ pkg/

 ENV CGO_ENABLED=0
-ENV GOOS=$TARGETOS
-ENV GOARCH=$TARGETARCH
+ENV GOOS=${TARGETOS:-linux}
+ENV GOARCH=${TARGETARCH:-amd64}
 ENV GO111MODULE=on

[isometry]

Thanks @jtackaberry! The Dockerfile hack is what operator-sdk is currently pushing (IIRC). I personally favour building a minimalist image with ko. My initial local patch actually included your fixes but I reverted in a misguided attempt to minimise the footprint of the patch after seeing other operators using the original pattern. Oh well. I'll update :-)

[isometry]

@jtackaberry : as per your suggestion, I've tidied up to remove unnecessary shenanigans.
The result is available at ghcr.io/isometry/aws-privateca-issuer:latest for testing.

[divyansh-gupta]

"BUILDPLATFORM is part of a set of automatically defined (global scope) build arguments that you can use. It will always match the platform or your current system and the builder will fill in the correct value for us."

from: https://www.docker.com/blog/faster-multi-platform-builds-dockerfile-cross-compilation-guide/

Putting this here for reference

[cert-manager-prow]

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