✨ tilt-prepare: add a flag to skip image preloading

[bnallapeta]

What this PR does / why we need it:

On Apple Silicon Macs, kind load docker-image fails for multi-arch images (like cert-manager) because Docker Desktop only stores the arm64 layers locally. This causes ctr to fail when it tries to import all architectures, resulting in a "content digest not found" error that blocks tilt up.
This PR updates tilt-prepare to skip the preloading step specifically on darwin/arm64. Instead of preloading, we rely on the Kubelet to pull the images on-demand when the pods start. This bypasses the kind/docker import issue and allows the development environment to start correctly.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #13142
Refs: kubernetes-sigs/kind#3795

/area devtools

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[chrischdi]

What this PR does / why we need it:

On Apple Silicon Macs, kind load docker-image fails for multi-arch images (like cert-manager) because Docker Desktop only stores the arm64 layers locally. This causes ctr to fail when it tries to import all architectures, resulting in a "content digest not found" error that blocks tilt up. This PR updates tilt-prepare to skip the preloading step specifically on darwin/arm64. Instead of preloading, we rely on the Kubelet to pull the images on-demand when the pods start. This bypasses the kind/docker import issue and allows the development environment to start correctly.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged): Fixes #13142 Refs: kubernetes-sigs/kind#3795

/area devtools

Note: this issue is also relevant when using docker community edition >= version 29 for any OS.

I think the workaround used in CI should work here too: using crane pull "$image" "image.tar" to pull the image and docker load -i "image.tar" to load it.

Afterwards preload work.

[bnallapeta]

What this PR does / why we need it:
On Apple Silicon Macs, kind load docker-image fails for multi-arch images (like cert-manager) because Docker Desktop only stores the arm64 layers locally. This causes ctr to fail when it tries to import all architectures, resulting in a "content digest not found" error that blocks tilt up. This PR updates tilt-prepare to skip the preloading step specifically on darwin/arm64. Instead of preloading, we rely on the Kubelet to pull the images on-demand when the pods start. This bypasses the kind/docker import issue and allows the development environment to start correctly.
Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged): Fixes #13142 Refs: kubernetes-sigs/kind#3795
/area devtools

Note: this issue is also relevant when using docker community edition >= version 29 for any OS.

I think the workaround used in CI should work here too: using crane pull "$image" "image.tar" to pull the image and docker load -i "image.tar" to load it.

Afterwards preload work.

Although crane would work, I am trying to avoid any dependencies for the user. Not everybody knows/uses crane in their local.
Secondly, even if we were to automate this, right now, crane isn't a tool in the tilt up workflow unlike the CI workflow.

That's why I chose the skipping way since that's probably the simplest and most straight forward. It just relies on the standard way of kubelet pulling images.

[chrischdi]

The thing is this does not exclusively fail for runtime.GOOS == "darwin" && runtime.GOARCH == "arm64" , it can also fail for any variant of running against docker. So with that arguing we could say "we should remove it for all".

The issue here is not >how we load the images< (which is part of the tooling) it is >how we pull the images<.

I'd favor a toggle-able option to disable it if needed. Long-term this should work.

[bnallapeta]

@chrischdi Got it. I have now updated the PR so that users could provide a flag in tilt-settings.yaml. PTAL.