Summary

Add platform-aware fallback validation for cluster autoscaling on EKS and GKE when Karpenter is absent. Also fix validator image pull policy for dev builds.

Motivation / Context

The cluster-autoscaling conformance check previously only validated Karpenter and skipped on all other clusters. EKS and GKE clusters that use native autoscaling (ASG node groups, GKE built-in cluster autoscaler) were incorrectly reported as skipped.

Fixes: N/A
Related: N/A

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Refactoring (no functional changes)
• Build/CI/tooling

Component(s) Affected

• CLI (cmd/aicr, pkg/cli)
• API server (cmd/aicrd, pkg/api, pkg/server)
• Recipe engine / data (pkg/recipe)
• Bundlers (pkg/bundler, pkg/component/*)
• Collectors / snapshotter (pkg/collector, pkg/snapshotter)
• Validator (pkg/validator)
• Core libraries (pkg/errors, pkg/k8s)
• Docs/examples (docs/, examples/)
• Other: ____________

Implementation Notes

Cluster autoscaling fallback (validators/conformance/cluster_autoscaling_check.go):

• Detects platform from node providerID (aws:// → EKS, gce:// → GKE)
• EKS: Validates GPU nodes belong to a managed node group via eks.amazonaws.com/nodegroup labels, scans all GPU nodes (not just first), optionally checks for Cluster Autoscaler deployment
• GKE: Validates GPU nodes, checks cluster-autoscaler-status ConfigMap, records node pool annotations and autoscaler events
• Fallback only triggers on ErrCodeNotFound (Karpenter truly absent). Unhealthy Karpenter is reported as a failure, not masked by fallback.
• Skips for unrecognized platforms (e.g., Kind)

Image pull policy fix (pkg/validator/job/deployer.go):

• Uses PullAlways for :latest tags (dev builds) to prevent stale cached images causing exec format error on cluster nodes
• Versioned tags continue to use PullIfNotPresent

Testing

go test -race ./validators/conformance/ -run 'Test(Check|Detect|Deref)' -count=1
go test -race ./pkg/validator/job/ -run 'TestImagePullPolicy' -count=1
golangci-lint run ./validators/conformance/ ./pkg/validator/job/

End-to-end conformance validation on real clusters:

• GKE aicr-demo4: 10/10 passed (cluster-autoscaling via GKE cluster autoscaler)
• EKS aicr-cuj1: 10/10 passed (cluster-autoscaling via EKS ASG node group)

Risk Assessment

• Low — Isolated change, well-tested, easy to revert

Rollout notes: N/A — additive change, existing Karpenter validation path unchanged.

Checklist

• Tests pass locally (make test with -race)
• Linter passes (make lint)
• I did not skip/disable tests to make CI green
• I added/updated tests for new functionality
• I updated docs if user-facing behavior changed
• Changes follow existing patterns in the codebase
• Commits are cryptographically signed (git commit -S) — GPG signing info