In Deckhouse Kubernetes Platform, you can implement the Locality failover mechanism using the istio module. Before configuring the mechanism, make sure the module is enabled in the cluster.

The Locality failover mechanism manages traffic routing and directs it to a priority failover in case certain service instances become unavailable.

If necessary, refer to the Locality failover documentation.

With Istio, you can configure priority-based geographic failover between endpoints. Zones are determined based on node labels in the following hierarchy:

  • topology.istio.io/subzone
  • topology.kubernetes.io/zone
  • topology.kubernetes.io/region

This is useful for inter-cluster failover when used together with multicluster configurations.

To enable Locality Failover, use the DestinationRule resource, which must also include the outlierDetection parameter.

Example:

apiVersion: networking.istio.io/v1beta1
kind: DestinationRule
metadata:
  name: helloworld
spec:
  host: helloworld
  trafficPolicy:
    loadBalancer:
      localityLbSetting:
        enabled: true # Enable LF.
    outlierDetection: # Required.
      consecutive5xxErrors: 1
      interval: 1s
      baseEjectionTime: 1m