Installing Cilium through its Helm chart is straightforward for teams with Kubernetes experience. The initial deployment replaces kube-proxy and the existing CNI with Cilium's eBPF-based data plane, which requires careful planning for production clusters to avoid connectivity interruptions. Documentation covers the migration path clearly, and the cilium connectivity test command validates the deployment before committing to production traffic.
Networking performance is where Cilium's eBPF foundation delivers measurable advantages. By processing packets in the kernel rather than through user-space proxies, Cilium achieves lower latency and higher throughput than iptables-based alternatives. The XDP integration enables wire-speed load balancing for north-south traffic, while socket-based load balancing for east-west traffic eliminates the per-packet NAT overhead that traditional kube-proxy implementations impose.
Network policy enforcement using identity-based labels rather than IP addresses is a conceptual leap that simplifies policy management at scale. Instead of tracking pod IP addresses that change frequently, Cilium assigns stable identities based on Kubernetes labels and enforces policies against those identities. This approach works naturally with Kubernetes' declarative model and scales to thousands of services without the iptables rule explosion problem.
Hubble provides network observability that rivals dedicated monitoring tools. The real-time flow visibility shows exactly which services communicate, what protocols they use, and whether traffic is being allowed or denied by policies. The service dependency map generated from actual traffic patterns is invaluable for understanding microservice architectures that have grown organically without clear documentation.
Tetragon adds security observability and runtime enforcement that extends Cilium's value beyond networking. Process execution monitoring, file access tracking, and network activity observation all operate through eBPF programs that impose minimal performance overhead. The ability to enforce security policies synchronously in the kernel, blocking malicious activity before it can complete, provides a defense layer that user-space tools cannot match in response time.
The Cluster Mesh feature for multi-cluster connectivity works well in practice for teams operating across regions or cloud providers. Global service discovery and cross-cluster load balancing enable architectures where services span clusters transparently, with identity-based policies applying consistently regardless of which cluster a pod runs in.
Service mesh capabilities have matured to cover basic traffic management use cases without requiring Istio or Linkerd. Mutual TLS, traffic splitting, and Layer 7 visibility through optional Envoy integration provide service mesh functionality for teams that need these capabilities but want to avoid the operational complexity of a full sidecar-based mesh deployment.
Documentation quality is good with comprehensive guides covering installation, configuration, and common operational tasks. The eBPF technology underlying Cilium has a steep learning curve for teams debugging complex networking issues, and some advanced configuration scenarios require deeper understanding of Linux kernel networking than typical Kubernetes operators possess.