v0.5.0: Startup hardening, max-pods support, and CI smoke tests

Release Notes

Summary

This release hardens pod-node startup reliability, adds CI validation for kubelet flag clamping, and improves operational diagnostics for vCluster Platform Auto Nodes.

Highlights

Reliability

• Restored stable cgroup startup flow (unshare + helper scripts) used by systemd/kubelet bootstrap.
• Added startup fail-fast checks in podnode-entrypoint.sh for required executables:
  • /entrypoint.sh
  • /usr/local/bin/podnode-clamp-allocatable.sh
  • /escape-cgroup.sh
  • /create-kubelet-cgroup.sh
• If required scripts are missing, container exits with a clear error message instead of failing later in bootstrap.

Node Sizing Behavior

• PODNODE_CPU and PODNODE_MEMORY continue to clamp kubelet allocatable via kubelet args patching.
• PODNODE_PODS support remains enabled and sets kubelet --max-pods.
• Kubelet arg patching remains idempotent (existing flags are replaced cleanly on reruns).

CI / Testing

• Added GitHub Actions CI workflow (.github/workflows/ci.yaml) for:
  • shell syntax checks
  • clamp smoke test execution
• Added smoke test (tests/smoke-clamp.sh) that verifies kubelet args updates include:
  • --kube-reserved
  • --system-reserved
  • --enforce-node-allocatable
  • reserved cgroup flags
  • --max-pods

Documentation

• README updated with:
  • clarified behavior around allocatable vs capacity
  • runtime diagnostics commands for troubleshooting
  • vCluster Platform Auto Nodes NodeProvider guidance and env/resource mapping

Operator Notes

• Use immutable image tags for NodeProvider updates.
• Ensure NodeProvider sets:
  • PODNODE_CPU
  • PODNODE_MEMORY
  • PODNODE_PODS
• Keep resources.requests == resources.limits for Guaranteed QoS.
• In this model, CPU/memory allocatable is clamped from env values; CPU/memory capacity may still reflect host-detected values.