Cilium turns Linux kernel eBPF into a complete networking stack that can replace kube-proxy, enforce L7 policies, and provide observability - all without performance penalties

Traditional Kubernetes networking hits a wall at scale. kube-proxy becomes a bottleneck, network policies are basic L3/L4 only, and observability requires bolt-on solutions that add latency. Cilium rewrites the playbook by moving all networking logic directly into the Linux kernel using eBPF - eliminating userspace overhead entirely.

This isn’t just another CNI plugin. Cilium completely replaces kube-proxy with eBPF hash tables that scale to thousands of services, enforces HTTP/gRPC/Kafka policies at L7 without proxies, and provides distributed load balancing with integrated ingress/egress gateways. The observability is surgical - you get flow logs, security events, and performance metrics with near-zero overhead because it’s all happening in kernel space.

As a CNCF graduated project with 23k+ stars, Cilium has proven itself in production at companies running massive Kubernetes clusters. The installation is surprisingly straightforward, and the Hubble UI gives you Netflix-level network visibility out of the box. If you’re hitting networking limits or want to see what modern Kubernetes infrastructure looks like, this is where the industry is heading.

⭐ Stars: 23594
💻 Language: Go
🔗 Repository: cilium/cilium