Kubernetes Service Meshes: mTLS and Multi-Cluster Architecture

Selecting a service mesh for a multi-cluster Kubernetes platform is an architecture and operations decision before it is a performance question. This report develops a requirement-driven method for selecting and validating a secure service-mesh profile for a representative multi-service application.  It traces request paths, workload identity, encryption and policy boundaries, discovery, trust distribution, lifecycle ownership, and failure dependencies, showing that similarly named mTLS and multi-cluster features can protect different hops and impose different constraints. A reproducible Robot Shop deployment, active security probes, controlled load, and Chaos Mesh faults validate the configured profiles.  The resulting architecture-first selection framework and operational run-book use performance and resilience evidence only after required security and topology semantics have been established.