Allow building storage-provisioner for other arch

[afbjorklund]

For #6007

Also allow building the static binary in docker

---

By setting GOARCH, you can cross-compile.
The default is to build for the local architecture.

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[codecov-io]

Codecov Report

Merging #6257 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #6257   +/-   ##
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  Coverage   38.23%   38.23%           
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  Files         123      123           
  Lines        8269     8269           
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  Hits         3162     3162           
  Misses       4696     4696           
  Partials      411      411

[priyawadhwa]

Instead of having a Dockerfile per architecture, could we pass in GOARCH as a build arg to docker build?

Then we could have one Dockerfile that looks like:

FROM scratch
ARG arch
COPY out/storage-provisioner-$(arch) storage-provisioner
CMD ["/storage-provisioner"]

and one docker build command:

docker build -t $(REGISTRY)/storage-provisioner:$(STORAGE_PROVISIONER_TAG) -f deploy/storage-provisioner/Dockerfile  --build-arg arch=$(GOARCH) .

[afbjorklund]

I think that will work, would be good to add arm support - and drop ubuntu for the s390x.

Can't really verify whether that (scratch) works on the mainframe, but... it's a static binary ?

[priyawadhwa]

My guess is it would work? But that's just a guess 😅

[afbjorklund]

I think you have to be really interested, to set up a test machine for s390x:

https://astr0baby.wordpress.com/2018/06/03/installing-ubuntu-18-04-server-s390x-in-hercules-mainframe-simulator/

I would be surprised if it was more than a binary number of minikube users on it ?

And even if minikube works ok on arm/arm64, we don't really support the desktop.

[afbjorklund]

@priyawadhwa : syntax was close enough, Dockerfile uses ${} while Makefile uses $()