Document node label in DR failover (#3104)

Author: howardjohn

networking/v1alpha3/destination_rule.pb.go

@@ -1307,6 +1307,7 @@ message LocalityLoadBalancerSetting{
     //   - `topology.kubernetes.io/region` is used to match the region metadata of an endpoint, which maps to Kubernetes node label `topology.kubernetes.io/region` or the deprecated label `failure-domain.beta.kubernetes.io/region`.
     //   - `topology.kubernetes.io/zone` is used to match the zone metadata of an endpoint, which maps to Kubernetes node label `topology.kubernetes.io/zone` or the deprecated label `failure-domain.beta.kubernetes.io/zone`.
     //   - `topology.istio.io/subzone` is used to match the subzone metadata of an endpoint, which maps to Istio node label `topology.istio.io/subzone`.
+    //   - `kubernetes.io/hostname` is used to match the current node of an endpoint, which maps to Kubernetes node label `kubernetes.io/hostname`.
     //
     // The below topology config indicates the following priority levels:
     //

networking/v1alpha3/destination_rule.pb.html

@@ -1256,6 +1256,7 @@ message LocalityLoadBalancerSetting{
     //   - `topology.kubernetes.io/region` is used to match the region metadata of an endpoint, which maps to Kubernetes node label `topology.kubernetes.io/region` or the deprecated label `failure-domain.beta.kubernetes.io/region`.
     //   - `topology.kubernetes.io/zone` is used to match the zone metadata of an endpoint, which maps to Kubernetes node label `topology.kubernetes.io/zone` or the deprecated label `failure-domain.beta.kubernetes.io/zone`.
     //   - `topology.istio.io/subzone` is used to match the subzone metadata of an endpoint, which maps to Istio node label `topology.istio.io/subzone`.
+    //   - `kubernetes.io/hostname` is used to match the current node of an endpoint, which maps to Kubernetes node label `kubernetes.io/hostname`.
     //
     // The below topology config indicates the following priority levels:
     //