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Service Internal Traffic Policy
Kubernetes v1.21 [alpha]
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
Once you have enabled the
you can enable an internal-only traffic policy for a
Services, by setting its
This tells kube-proxy to only use node local endpoints for cluster internal traffic.
Note: For pods on nodes with no endpoints for a given Service, the Service behaves as if it has zero endpoints (for Pods on this node) even if the service does have endpoints on other nodes.
The following example shows what a Service looks like when you set
apiVersion: v1 kind: Service metadata: name: my-service spec: selector: app: 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
When the feature gate
ServiceInternalTrafficPolicy is enabled,
spec.internalTrafficPolicy defaults to "Cluster".
- Service Internal Traffic Policy is not used when
externalTrafficPolicyis set to
Localon a Service. It is possible to use both features in the same cluster on different Services, just not on the same Service.
- Read about enabling Topology Aware Hints
- Read about Service External Traffic Policy
- Read Connecting Applications with Services