Copper and Wire: Bridging Expressiveness and Performance for Service Mesh Policies

Distributed microservice applications require a convenient means of controlling L7 communication between services. Service meshes have emerged as a popular approach to achieving this. However, current service mesh frameworks are difficult to use -- they burden developers in realizing even simple communication policies, lack compatibility with diverse dataplanes, and introduce performance and resource overheads. We identify the root causes of these drawbacks and propose a ground-up new mesh architecture that overcomes them. We develop novel abstractions for mesh communication, a new mesh policy language centered on these abstractions to enable expressive policies, and a novel control plane that enables using minimal dataplane resources for policy enforcement. We develop the precise semantics of our language abstractions and demonstrate how our control plane can use them to execute policies correctly and optimally. We build and evaluate a prototype on realistic workloads and policies and open-source production traces. Our results show that complex policies can be specified in up to 6.75× fewer lines, enforced with up to 2.6× smaller tail latencies and up to 39% fewer CPU resources than today.