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Cilium

eBPF-based networking, security, and observability for Kubernetes

Cilium is a CNCF Graduated, Apache-2.0 project for Kubernetes networking, security, and observability using eBPF. It can replace kube-proxy, enforce identity-aware L3-L7 network policies, and add Hubble flow observability plus Tetragon runtime-security signals. Current source checks support GKE Dataplane V2 using Cilium/eBPF and Azure CNI Powered by Cilium for AKS.

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About Cilium

Cilium is a CNCF Graduated Kubernetes networking, security, and observability project that uses eBPF to move datapath, policy, and visibility logic closer to the Linux kernel. The project is Apache-2.0, active on GitHub with 24K+ stars, and documented around Cilium 1.19.x at the time of this update. Its core value is giving Kubernetes teams an eBPF-based alternative to older iptables-heavy networking and policy paths.

The source-backed cloud story should be precise. Google Cloud documentation says GKE Dataplane V2 is implemented using Cilium and eBPF and is enabled by default for new Autopilot clusters, while Microsoft documents Azure CNI Powered by Cilium for AKS. Those facts are stronger and safer than broad claims that every major cloud provider has made Cilium the default networking layer in every Kubernetes offering.

Cilium’s surrounding ecosystem adds Hubble for flow observability, Tetragon for runtime-security observability and enforcement, Cluster Mesh for multi-cluster connectivity, and service-mesh-adjacent features such as mutual TLS, Gateway API integration, and Layer 7 protocol visibility. Teams should still plan migrations carefully and keep dedicated service-mesh platforms in scope when they need advanced L7 traffic management.

Pricing & Platform Specs

Pricing Summary

Free and 100% open source under the Apache-2.0 license (with dual GPL-2.0/BSD-2-Clause BPF datapath templates) as a CNCF Graduated project. Cilium has no software licensing fees for self-hosted or cloud Kubernetes deployments (including GKE Dataplane V2 and Azure CNI Powered by Cilium); organizations pay only for their compute infrastructure. For mission-critical enterprise environments, Isovalent Enterprise for Cilium (by Cisco) provides quote-based annual subscriptions (per-node/environment) with 24/7 SLA support, hardened LTS builds, Customer Testing Environments (CuTEs), enterprise BGP/EVPN, and advanced multi-cluster security and observability retention.

full pricing breakdown →

Supported Platforms

Linux, Kubernetes, Helm installation

Explore categories, tags & use cases

Alternatives

All Cilium alternatives →
Coroot logo

Coroot

Zero-instrumentation Kubernetes observability powered by eBPF

Coroot is an open-source observability platform that uses eBPF to automatically instrument Kubernetes applications without code changes. It provides application maps, latency analysis, log correlation, and continuous profiling with automatic anomaly detection. Replaces the need for manual instrumentation with agents that capture metrics, traces, and logs at the kernel level.

freemiumOpen Source
k0s logo

k0s

Zero-friction single-binary Kubernetes distribution by Mirantis

k0s is a lightweight, CNCF-certified Kubernetes distribution packaged as a single binary with zero host dependencies. Backed by Mirantis, it simplifies cluster deployment by bundling all required components into one executable that works on any Linux system. Supports x86-64, ARM64, and ARMv7 architectures with automatic upgrades and a built-in control plane load balancer.

freemiumOpen Source

Side-by-Side Comparisons

Cilium logo
Cilium
vs
Istio logo
Istio

Cilium vs Istio — eBPF Kernel-Level Networking vs Envoy Sidecar Service Mesh

Cilium and Istio both manage Kubernetes service-to-service communication but use fundamentally different architectural approaches. Cilium leverages eBPF programs in the Linux kernel to handle networking, security, and observability without user-space proxies. Istio deploys Envoy sidecar proxies alongside each pod for traffic management, mutual TLS, and fine-grained routing with deep Layer 7 protocol awareness.

CiliumIstio

Community experience

Sources & verification

Sources checked
Content verified

Verification dates are editorial checks. Routine CMS saves and automatic updatedAt timestamps do not advance them.

FAQ

What is Cilium?

Cilium is a CNCF Graduated, Apache-2.0 project for Kubernetes networking, security, and observability using eBPF. It can replace kube-proxy, enforce identity-aware L3-L7 network policies, and add Hubble flow observability plus Tetragon runtime-security signals. Current source checks support GKE Dataplane V2 using Cilium/eBPF and Azure CNI Powered by Cilium for AKS.

Is Cilium free?

Yes — Cilium is open source and free to use. Free and 100% open source under the Apache-2.0 license (with dual GPL-2.0/BSD-2-Clause BPF datapath templates) as a CNCF Graduated project. Cilium has no software licensing fees for self-hosted or cloud Kubernetes deployments (including GKE Dataplane V2 and Azure CNI Powered by Cilium); organizations pay only for their compute infrastructure. For mission-critical enterprise environments, Isovalent Enterprise for Cilium (by Cisco) provides quote-based annual subscriptions (per-node/environment) with 24/7 SLA support, hardened LTS builds, Customer Testing Environments (CuTEs), enterprise BGP/EVPN, and advanced multi-cluster security and observability retention.

Is Cilium open source?

Yes — Cilium is open source.

Is Cilium still maintained?

Yes — Cilium is active. Its listing was last verified on September 6, 2026.

What are the best Cilium alternatives?

The first editor-selected Cilium alternatives are Coroot, k0s.

How does Cilium score in our review?

The published editorial review lists Cilium at 93/100 overall across speed, privacy, and developer experience. Check the review's evidence status and test metadata for its verification level.