Istio
also: service mesh
Istio is an open-source service mesh that manages communication between microservices in Kubernetes clusters, providing traffic management, security, and observability without requiring application code changes.
Istio is a service mesh platform that runs alongside your Kubernetes applications and intercepts all network communication between services. It uses sidecar proxies (typically Envoy) deployed in each pod to manage traffic routing, load balancing, and security policies at the infrastructure level.
Common use cases include: implementing canary deployments (gradually rolling out new versions), enforcing mutual TLS encryption between services, applying fine-grained traffic policies, and collecting detailed metrics about service-to-service communication without modifying application code.
For example, you can configure Istio to route 90% of traffic to version 1 of a service and 10% to version 2 for testing, then automatically fail over if latency exceeds thresholds—all through Istio configuration rather than application logic.
Istio adds complexity and resource overhead, so it's typically used in larger microservices deployments where you need sophisticated traffic control and observability across many services.