DevOps Dictionary

Istio is an open-source service mesh that adds a consistent layer of security, traffic control, and observability across microservices without requiring each service to implement those capabilities itself. It typically works by deploying a sidecar proxy alongside each service instance and using a central control plane to configure those proxies, so all service-to-service requests can be encrypted (mTLS, or mutual TLS), authenticated, routed, retried, and measured in a uniform way.

With Istio, teams can enforce policies and gain reliable telemetry (metrics, logs, traces) across many services from one place; without it, these concerns are often reimplemented inconsistently in application code, leading to uneven security, harder debugging, and riskier deployments. This gap exists because distributed systems fail in partial and unpredictable ways, and handling those failures correctly is difficult to standardize at the application level.