DevOps Dictionary

Istio is an open-source service mesh that adds a dedicated control layer for securing, observing, and managing communication between microservices in Kubernetes and other environments. It works by deploying lightweight “sidecar” proxies alongside each service to handle traffic, enforce policies, and collect telemetry (metrics, logs, and traces) without requiring application code changes. This centralizes capabilities like mutual TLS (encrypted, authenticated service-to-service connections), traffic routing for safe rollouts, retries and timeouts, and access controls.

With Istio, operators can apply consistent security and reliability rules across many services and gain uniform visibility into failures and latency; without it, each team typically implements these concerns differently, leading to uneven security posture, harder debugging, and brittle networking behavior at scale. This gap exists because service-to-service communication becomes a distributed system problem, and a mesh standardizes how that communication is governed and measured.