
The article dissects linkerd-destination, the core component of Linkerd’s control plane that drives service discovery, policy distribution, and service‑profile enforcement. It explains how the service uses Kubernetes watches and EndpointSlices to translate cluster events into real‑time gRPC streams for proxies. Internal architecture is split across four containers—destination, SP‑validator, policy, and an injected proxy—ensuring separation of concerns and mTLS security. The author also highlights key metrics that reveal control‑plane health and the impact of a degraded destination service.

Linkerd’s lightweight service mesh automatically detects the protocol of incoming connections by inspecting the first bytes, enabling features such as HTTP metrics, retries, and load‑balancing without manual annotations. The detection logic recognises HTTP/1.x, HTTP/2, gRPC, TLS and falls back to...