"The concept of the service mesh as a separate layer is tied to the rise of the cloud native application. In the cloud native model, a single application might consist of hundreds of services; each service might have thousands of instances; and each of those instances might be in a constantly-changing state as they are dynamically scheduled an orchestrator like Kubernetes. Not only is service communication in this world incredibly complex, it’s a pervasive and fundamental part of runtime behavior. Managing it is vital to ensuring end-to-end performance and reliability."

https://blog.buoyant.io/2017/04/25/whats-a-service-mesh-and-...