In this chapter, we learned about the service mesh concept and Istio, an open source project that implements it. A service mesh provides capabilities for handling challenges in a system landscape of microservices in areas such as security, policy enforcement, resilience, and traffic management. A service mesh can also be used to make a system landscape of microservices observable by visualizing the traffic that flows through the microservices.
For observability, Istio uses Kiali, Jaeger, and Grafana (more on Grafana in Chapter 20, Monitoring Microservices). When it comes to security, Istio can be configured to use a certificate to protect external APIs with HTTPS and require that external requests contain valid JWT-based OAuth 2.0/OIDC access tokens. Finally, Istio can be configured to automatically protect internal communication using mutual authentication (mTLS)...