Definition
A service mesh is a dedicated infrastructure layer for handling service to service communication within a distributed application. It abstracts the network, making it easier for developers to manage, observe, and secure microservices. A service mesh typically operates by deploying a proxy, known as a sidecar, alongside each service instance. This allows for centralized control over traffic routing, security policies, and observability without altering application code. Understanding service meshes is crucial for building resilient and scalable cloud-native applications. For instance, a service mesh can automatically reroute traffic away from an unhealthy service instance to a healthy one. It is distinct from an API gateway, which typically handles external traffic entering the system. Service meshes are relevant to cloud architecture discussions and can appear on advanced cloud certification exams.