LimitRange defaults had a 4-8x limit/request ratio causing the scheduler
to overpack nodes. When pods burst, nodes OOM-thrashed and became
unresponsive (k8s-node3 and k8s-node4 both went down today).
Changes:
- Increase default memory requests across all tiers (ratio now 2x):
- core/cluster: 64Mi → 256Mi request (512Mi limit)
- gpu: 256Mi → 1Gi request (2Gi limit)
- edge/aux/fallback: 64Mi → 128Mi request (256Mi limit)
- Add kubelet memory reservation and eviction thresholds:
- systemReserved: 512Mi, kubeReserved: 512Mi
- evictionHard: 500Mi (was 100Mi), evictionSoft: 1Gi (was unset)
- Applied to all nodes and future node template
fffc2ed0ab