You are viewing documentation for Kubernetes version: v1.24

Kubernetes v1.24 documentation is no longer actively maintained. The version you are currently viewing is a static snapshot. For up-to-date documentation, see the latest version.

Service Internal Traffic Policy

FEATURE STATE: Kubernetes v1.23 [beta]

Service Internal Traffic Policy enables internal traffic restrictions to only route internal traffic to endpoints within the node the traffic originated from. The "internal" traffic here refers to traffic originated from Pods in the current cluster. This can help to reduce costs and improve performance.

Using Service Internal Traffic Policy

The ServiceInternalTrafficPolicy feature gate is a Beta feature and enabled by default. When the feature is enabled, you can enable the internal-only traffic policy for a Services, by setting its .spec.internalTrafficPolicy to Local. This tells kube-proxy to only use node local endpoints for cluster internal traffic.

The following example shows what a Service looks like when you set .spec.internalTrafficPolicy to Local:

apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  selector:
    app.kubernetes.io/name: MyApp
  ports:
    - protocol: TCP
      port: 80
      targetPort: 9376
  internalTrafficPolicy: Local

How it works

The kube-proxy filters the endpoints it routes to based on the spec.internalTrafficPolicy setting. When it's set to Local, only node local endpoints are considered. When it's Cluster or missing, all endpoints are considered. When the feature gate ServiceInternalTrafficPolicy is enabled, spec.internalTrafficPolicy defaults to "Cluster".

What's next

Last modified July 11, 2022 at 8:41 AM PST: [en] update en docs to use recommended labels (f9ebc90ff7)