Zero Trust Microservices Architectures: Envoy Gateway, eBPF & Mutual TLS at Enterprise Scale

Traditional firewalls assume internal traffic is inherently safe. Zero Trust models mandate strict cryptographic authentication and fine grained authorization for every single inter service RPC. Every microservice must prove its cryptographic identity, encrypt all payloads in transit via mutual TLS (mTLS), and possess explicit least privilege permissions before communicating.

Migrating away from fragile Ingress controllers, Envoy Gateway standardizes L4/L7 routing through the expressive Kubernetes Gateway API. It unifies rate limiting, JWT token validation, global CORS policies, and automated Let's Encrypt certificate rotations at the edge cluster boundary with declarative GitOps manifests.

Injecting an Envoy sidecar proxy into every application pod introduces memory bloat (50MB-150MB per pod) and added network hops. Using eBPF powered networking with Cilium, packet inspection, encryption, and routing happen directly within the Linux kernel socket layer. This slashes network latency by up to 80% while enforcing transparent mTLS identity verification.

IP addresses and DNS names are ephemeral and easily spoofed. By leveraging SPIFFE verifiable identity documents (SVIDs) backed by SPIRE agents, workloads receive short lived X.509 cryptographic certificates tied to hardware TPMs and Kubernetes service accounts, preventing lateral movement even if an attacker gains root access to a container.