What is Envoy and Gateway API in Kubernetes?

Envoy is a high-performance open-source proxy server used as a service mesh or edge proxy. It provides routing, load balancing, observability, security, and other features for microservices. In Kubernetes, Envoy is often used as a sidecar proxy in a service mesh (e.g., Istio).

Gateway API is a set of extensible Kubernetes resources designed to manage incoming traffic to the cluster. It offers a more flexible and expressive way to describe routes, routing rules, and gateway configurations compared to the traditional Ingress.

Relationship:

• Envoy can serve as the implementation of a Gateway (Gateway Controller), handling traffic according to rules defined via Gateway API.
• Gateway API allows declarative description of how traffic should be routed, and Envoy implements these rules in practice.

Key features of Gateway API:

• Support for multiple gateway types (e.g., HTTP, TCP).
• Separation of responsibilities between teams (e.g., administrators manage Gateways, developers manage Routes).
• Extensibility and more precise control over routing.

Thus, Envoy is a technical implementation of a proxy, and Gateway API is a Kubernetes standard for describing and managing incoming traffic, which can use Envoy as a controller.