xDS (Discovery Service Protocol)

A family of gRPC-based data plane APIs used by Envoy Proxy and compatible proxies to receive dynamic configuration from a control plane without restarts. xDS encompasses: LDS (Listener Discovery Service) for TCP/UDP listeners, RDS (Route Discovery Service) for HTTP routing rules, CDS (Cluster Discovery Service) for upstream clusters, EDS (Endpoint Discovery Service) for cluster member endpoints, and SDS (Secret Discovery Service) for TLS certificates. Service mesh control planes — Istio (Istiod), Consul Connect, AWS App Mesh — speak xDS to configure their Envoy data planes. The xDS API is also used by non-Envoy proxies such as gRPC's built-in load balancer for server-side load balancing.