Istio

Prerequisite: Before reading this part, please review Part 1: Architectural Decision Framework. Part 2: FinOps Cost Reality - The “Hidden Tax” of Microservices Answer-first: Microservices impose substantial hidden infrastructure costs: sidecar proxy memory overhead, cross-AZ data transfer fees ($0.02/GB), NAT Gateway processing, and high-cardinality logging ingestion. A modular monolith co-locates domain execution within a single container and private subnet, eliminating cross-service network serialization fees and cutting AWS infrastructure bills by up to 90% without sacrificing domain modularity. ...

Answer-first: API Gateways govern north-south ingress traffic crossing untrusted perimeter boundaries, executing edge authentication, rate limiting, and protocol translation. Conversely, Service Meshes manage east-west internal pod-to-pod communication, enforcing mutual TLS zero-trust identity, distributed telemetry, and traffic shifting. Rather than competing alternatives, modern architectures deploy both symbiotically, with eBPF sockops bypassing kernel TCP stacks to eliminate sidecar proxy latency. Prerequisite: In-depth knowledge of OSI Layer 4/Layer 7 networking, Kubernetes Ingress and Gateway API specifications, Envoy proxy architecture, and mutual TLS fundamentals is required for this chapter. ...

Zero-Trust Service Mesh Security in Go: SPIFFE/SPIRE & Istio Answer-first: Zero-trust service mesh security in Go uses SPIFFE/SPIRE identity attestation and Istio mTLS to enforce cryptographically verified workload identities and least-privilege API access. Introduction: The Zero-Trust Imperative in Modern Financial Microservices Traditional perimeter security models relying on firewalls, Virtual Private Clouds, and static IP addresses fail to protect modern microservices processing sensitive payment data. Container IP addresses are ephemeral and static Kubernetes secrets risk exposure, so enterprise financial architectures need Zero-Trust models that cryptographically authenticate every inter-service communication. ...