Experimenting with ClusterNetworkPolicy in GKE
đź”’ This post demonstrates using ClusterNetworkPolicy (CNP) in Google Kubernetes Engine (GKE) to enforce cluster-wide, multi-tier networking controls. It describes an experiment protecting an LLM workload (Gemma 4) running on TPU-backed GKE nodes and shows how CNP admin, network policy, and baseline tiers interact. The setup includes a custom VPC, Cloud NAT, GKE Dataplane V2 (eBPF), and namespace-scoped NetworkPolicies to allow only authorized clients while blocking metadata access.