How do you implement service mesh architecture with Istio in Kubernetes and what are the benefits?

Istio service mesh provides advanced traffic management, security, and observability for microservices without requiring application code changes.\n\nIstio Architecture:\n• Data Plane: Envoy proxies as sidecars\n• Control Plane: Istiod (Pilot, Citadel, Galley)\n• Ingress/Egress Gateways: Traffic entry/exit points\n• Custom Resource Definitions for configuration\n\nCore Features:\nTraffic Management:\n• Intelligent routing and load balancing\n• Circuit breakers and retries\n• Traffic splitting for canary deployments\n• Fault injection for testing\n\nSecurity:\n• Mutual TLS (mTLS) encryption\n• Identity-based authentication\n• Authorization policies\n• Certificate management\n\nObservability:\n• Distributed tracing\n• Metrics collection\n• Access logging\n• Service topology visualization\n\nExample Configuration:\napiVersion: networking.istio.io/v1beta1\nkind: VirtualService\nmetadata:\n name: reviews\nspec:\n http:\n - match:\n - headers:\n end-user:\n exact: jason\n route:\n - destination:\n host: reviews\n subset: v2\n - route:\n - destination:\n host: reviews\n subset: v1\n weight: 90\n - destination:\n host: reviews\n subset: v3\n weight: 10\n\nBest Practices:\n• Gradual rollout with sidecar injection\n• Monitor service mesh performance overhead\n• Implement proper mTLS policies\n• Use Kiali for visualization\n• Configure appropriate resource limits\n• Regular security policy audits