Cilium delivers networking, security, and observability for cloud native environments such as Kubernetes clusters on an eBPF-based data plane. Core capabilities include a flat Layer 3 network across clusters, kube-proxy replacement, load balancing, transparent encryption, identity-based network policy, and a sidecar-free service mesh with Gateway API support.
Hubble provides network flow observability with metrics, service maps, and Layer 3 to Layer 7 visibility, while Tetragon provides security observability and runtime enforcement. The software runs as the container network interface in managed Kubernetes services including Google GKE Dataplane V2, Amazon EKS Anywhere, and Azure CNI powered by Cilium.
The Cilium roadmap extends the platform beyond Kubernetes to external workloads including virtual machines and bare metal, alongside early Gateway API support and a standalone Layer 4 load balancer for north-south traffic. The 2025 annual report describes expanding use cases that include large-scale AI infrastructure.
Following Cisco acquisition of Isovalent, Cisco committed to nurturing the eBPF, Cilium, and Tetragon communities under an independent advisory board, indicating continued vendor investment in the open-source ecosystem.
The eBPF-based data plane operates in the kernel, giving Cilium performance and identity-aware visibility without sidecars, and the project introduced a sidecar-free service mesh. All three major public cloud providers selected Cilium for managed Kubernetes networking, and it is the default network layer in Google GKE and Anthos and in Amazon EKS Anywhere.
The project counts more than 1,000 developers and dozens of public case studies, with adopting organizations including Bell Canada, Bloomberg, DB Schenker, S&P Global, Sky, and The New York Times. Community adoption spans cloud providers, software vendors, financial services firms, and e-commerce platforms.
Cilium is free open-source software with no paid tiers on the project site. Commercial support, hardened enterprise distributions, training, and certification are offered by ecosystem partners rather than by the project itself.
Listed partners include Isovalent, now part of Cisco, for the enterprise distribution, plus acend, KodeKloud, and Linux Foundation Training for training and certification. The Cilium Certified Associate certification is administered through the Linux Foundation.
