Locality Load Balancing

    A locality defines the geographic location of a workload instance within your mesh. The following triplet defines a locality:

    • Region: Represents a large geographic area, such as us-east. A region typically contains a number of availability zones. In Kubernetes, the label determines a node’s region.

    If you are using a hosted Kubernetes service your cloud provider should configure the region and zone labels for you. If you are running your own Kubernetes cluster you will need to add these labels to your nodes.

    Localities are hierarchical, in the matching order:

    1. Region

    2. Sub-zone

    That means that a pod running in zone bar of region is not considered to be local to a pod running in zone bar of region .

    Istio uses this locality information to control load balancing behavior. Follow one of the tasks in this series to configure locality load balancing for your mesh.