Cilium

Cilium is the emerging standard for Kubernetes networking and security, replacing iptables-based network plugins with eBPF — a technology that allows programmable kernel-level packet processing without kernel module development. The practical implication: Cilium can enforce network policies with microsecond latency overhead (vs milliseconds for iptables at scale), provide deep observability into network flows via Hubble, and implement transparent encryption between pods without a service mesh. Cilium was selected as the default CNI for Amazon EKS and GKE, which is the clearest signal of industry direction. For teams running large Kubernetes clusters where network policy is a security requirement, migrating to Cilium is the single highest-leverage infrastructure change available.