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 enforces cryptographic workload identities using SPIFFE/SPIRE kernel attestation (cgroups, namespaces, image digests) and Istio STRICT mTLS, eliminating static credentials. Rotating short-lived X.509 SVID certificates in memory every hour guarantees zero downtime, while fine-grained AuthorizationPolicy rules restrict inter-service communication to least-privilege paths complying with PCI-DSS 4.0 requirements. Prerequisite: Production familiarity with Kubernetes ServiceAccount tokens, Linux kernel cgroups and process namespaces, TLS 1.3 mutual authentication handshakes, and Go 1.25 network programming with gRPC transport. ...