Spin up 10 microservices, new problems begin. How does service-a know service-b's IP? When service-b suddenly returns 5xx, how fast should service-a retry? To encrypt all comms with mTLS, who issues and rotates certificates? For canary-deploying new versions to 10% traffic, where does routing split? Solving all in application code bloats it with infrastructure logic. Service mesh moves this problem to sidecar proxies outside code. SAP exams frequently ask scenarios distinguishing AWS' three options: Cloud Map, ECS Service Connect, App Mesh.
This article examines why service mesh emerged, how sidecar proxies intercept traffic, responsibility division