fix(templates): runtime Kubernetes arch detection for arm64

[ArangoGutierrez]

Summary

• Replace hardcoded amd64 default for Kubernetes arch with runtime detection
• Use dpkg --print-architecture (falls back to uname -m mapping)
• Affects kubeadm, kubelet, kubectl, CNI plugins, and crictl binary downloads
• User-specified Arch still takes precedence

Test plan

• Unit test verifies template output uses runtime detection when Arch is empty
• Unit test verifies template output uses user value when Arch is explicitly set
• go test ./pkg/provisioner/templates/... -v passes
• CI validation pending

[Copilot]

Pull request overview

This PR fixes a bug where the Kubernetes provisioner templates were hardcoded to use amd64 architecture by default, preventing proper installation on ARM64 systems. The fix introduces runtime architecture detection using dpkg --print-architecture with a fallback to uname -m, while still allowing users to explicitly specify the architecture.

Changes:

• Replaced hardcoded amd64 default with runtime detection in three Kubernetes templates (kubeadm, git source, latest source)
• Removed the hardcoded assignment in NewKubernetes function
• Added comprehensive test coverage for architecture detection behavior

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
pkg/provisioner/templates/kubernetes.go	Updated three template definitions to use conditional architecture detection and removed hardcoded default from NewKubernetes function
pkg/provisioner/templates/kubernetes_test.go	Updated existing tests to expect empty Arch (runtime detection) and added new tests validating runtime detection vs explicit arch for all three source types

[coveralls]

Pull Request Test Coverage Report for Build 22021792600

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 9 unchanged lines in 1 file lost coverage.
• Overall coverage remained the same at 47.856%

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Files with Coverage Reduction	New Missed Lines	%
pkg/provisioner/templates/kubernetes.go	9	85.12%

Totals
Change from base Build 21999063489:	0.0%
Covered Lines:	2567
Relevant Lines:	5364

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💛 - Coveralls

[ArangoGutierrez]

Closing as superseded. The equivalent fixes were already merged into main via PRs #661-664:

• feat(aws): AMI architecture detection and cross-validation #664: feat(aws): AMI architecture detection and cross-validation
• fix(aws): propagate architecture in cluster mode #661: fix(aws): propagate architecture in cluster mode
• fix(templates): dynamic CUDA repo arch for arm64 support #662: fix(templates): use runtime arch for NVIDIA CUDA repository URL
• fix(templates): runtime Kubernetes arch detection for arm64 #663: fix(templates): detect Kubernetes arch at runtime instead of defaulting to amd64

Additionally, these fixes address downstream provisioning issues but do not resolve the actual EC2 RunInstances failure (Unsupported: The requested configuration is currently not supported) reported in https://github.com/NVIDIA/gpu-driver-container/actions/runs/22012665274/job/63611032634. The root cause is missing architecture inference from instance type — when image.architecture is unset, holodeck defaults to x86_64 regardless of the instance type. A new PR will address this.