eBPF and Cilium — Service Mesh Without Sidecar Proxies

Istio with Envoy sidecar proxies on every pod. Great — but also overhead. Cilium takes a radically different approach: eBPF in the kernel. No sidecars. And the results are impressive.

eBPF — A Programmable Kernel¶

eBPF allows running sandboxed programs directly in the Linux kernel. For networking: filtering, routing, load balancing, and observability with minimal overhead.

Cilium as a Service Mesh¶

Sidecar-free: mTLS, traffic management, L7 policy — all without Envoy proxies. Since version 1.14, Cilium is a graduated CNCF project. Latency overhead measured in microseconds.

Hubble — Observability¶

Network flows, DNS queries, HTTP requests — at the kernel level. No agents, no code instrumentation.

Migration from Istio¶

• P99 latency: reduced by 40%
• Memory per pod: ~50MB saved (no Envoy sidecar)
• Operational complexity: significantly lower
• Observability: better (Hubble vs. Kiali)

eBPF Is the Future of Kubernetes Networking¶

Requires a modern kernel (5.10+). For organizations with large clusters and latency-sensitive workloads, it’s the clear choice.