What is Kubernetes Gateway API?

Question

Accepted Answer

**Gateway API** — next generation API for traffic routing in Kubernetes, replacing Ingress.

**Ingress problems:** scattered annotations, limited functionality, no native TCP/gRPC support.

**Core resources:**
- **GatewayClass** — defines the implementation (similar to StorageClass).
- **Gateway** — entry point (Listeners, TLS).
- **HTTPRoute** — HTTP traffic routing.
- **GRPCRoute**, **TCPRoute**, **TLSRoute** — other protocols.

**Example:**
```yaml
apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: my-gateway
  namespace: production
spec:
  gatewayClassName: istio
  listeners:
    - name: https
      protocol: HTTPS
      port: 443
      tls:
        mode: Terminate
        certificateRefs:
          - name: my-tls
      allowedRoutes:
        namespaces:
          from: Same
---
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: my-route
  namespace: production
spec:
  parentRefs:
    - name: my-gateway
  hostnames:
    - "myapp.com"
  rules:
    - matches:
        - path:
            type: PathPrefix
            value: /api
      backendRefs:
        - name: api-service
          port: 8080
    - matches:
        - headers:
            - name: x-canary
              value: "true"
      backendRefs:
        - name: api-service-v2
          port: 8080
      filters:
        - type: RequestHeaderModifier
          requestHeaderModifier:
            add:
              - name: x-served-by
                value: canary
```

**Advantages over Ingress:** native TCP/gRPC support, role-oriented model, portable (works with any controller), built-in header-based routing support.

DevOps: What is Kubernetes Gateway API?