DevOps Dictionary

Istio is an open-source service mesh that provides a shared layer for securing, controlling, and observing traffic between microservices without baking those concerns into every application. It works by running a lightweight proxy alongside each service instance and using a control plane to configure those proxies, so service-to-service calls can be encrypted with mutual TLS (mTLS), authenticated, routed with fine-grained rules, and measured consistently through metrics, logs, and traces.

With Istio, platform teams can apply uniform policies and get reliable telemetry across many services from a central place; without it, each service tends to implement security and traffic logic differently, leading to inconsistent protections, harder debugging, and riskier rollouts. This gap exists because distributed systems fail in partial, unpredictable ways, and handling retries, timeouts, and identity correctly is difficult to standardize in application code.