[WIP] Load defaults from versions.yaml for podvm build

[tumberino]

Built off of #1018

• Renamed existing Makefile to Makefile.image
• Refactored existing Makefile to target Docker image build process
• Created Makefile.defaults to load the required values from versions.yaml

Files Updated (Excluding changes from 1018)

• hack/yq.sh
• podvm/Makefile
• podvm/Makefile.image
• podvm/Makefile.default

[tumberino]

@yoheiueda could you take a look at the Makefile changes (excluding the Makefile.defaults for now) and see if it is worth adding into your #1018 ?

[yoheiueda]

@jtumber-ibm Your proposed change looks good to me.

With your change, we can build a builder image from the remote repo based on centos by this.

make docker-builder-remote-centos

And, we can build a builder image from the remote repo based on centos by this.

make docker-podvm-local-ubuntu

One thing I noticed is that my proposed Dockefile refactoring requires docker buildx, so I think it is better to use docker buildx build explicitly.

Another point is that how we can support podman build in addition to docker.

So, is it possible to parameterize the container image build command like this?

BUILD_CMD = docker buildx build

Then, we can change the build command like this.

make BUILD_CMD='podman build' build-podvm-local-ubuntu

@bpradipt any comments?

[yoheiueda]

I think the Makefile.defaults part is work-in-progress, and you are possibly working on a similar idea, but I think we can define a fuction like below to reduce redundancy. (I don't come up with a good function name though.)

define query
	$(or $(shell $(YQ_PATH) '.$(1) | select(. != null)' $(VERSIONS_SRC)), \
	     $(error $(1) is not set, and could not be automatically set from $(VERSIONS_SRC)))
endef

ubuntu_amd64_IMAGE_URL ?= $(call query,cloudimg.ubuntu.focal.amd64.url)

[tumberino]

@yoheiueda from a quick test it seems that podman doesn't support only building the required stages

[yoheiueda]

Thank you for the investigation! Probably, we can support docker buildx only for the time being.

[katexochen]

IMO downloading executables transparently isn't a good practice. Maybe we could warn that something required is missing instead?

[katexochen]

Maybe we could improve reproducibility and traceability of these build if we don't set any defaults at all. The source of truth should be the versions.yaml file, right?