Is Ambient Mesh the Future of Service Mesh?

Ambient mesh is often touted as a more efficient evolution of service mesh technology due to its leaner, simpler design, and reduced resource usage by eliminating sidecars from every pod. It operates by using a single ztunnel daemon for L4 traffic, which efficiently manages mutual TLS and routing, offering significant CPU and memory savings in high-density environments. However, this resource efficiency introduces operational complexities, especially for L7 traffic that requires centralized Waypoint proxies, adding extra hops and necessitating careful planning to avoid bottlenecks. Sidecar-based meshes, while incurring a higher resource footprint, offer greater operational simplicity, predictability, and isolation, making them suitable for environments that prioritize compliance, team autonomy, and detailed observability. They allow independent scaling and telemetry, reducing operational risks. For mission-critical, multi-zone, or regulated environments, sidecar-based meshes remain the preferred choice due to their maturity and enterprise-grade capabilities, while ambient mesh is more suited for lightweight, L4-dominant applications in single-cluster settings. Despite the promise of ambient mesh, it is still in early stages, and even key proponents like Istio suggest caution in adopting it for mission-critical environments.