plugin/kubernetes: Don't use pod names longer than 63 characters as dns labels (#4908)

Automatically submitted.

plugin/kubernetes/README.md

@@ -87,7 +87,7 @@ kubernetes [ZONES...] {
    If this directive is included, then name selection for endpoints changes as
    follows: Use the hostname of the endpoint, or if hostname is not set, use the
    pod name of the pod targeted by the endpoint. If there is no pod targeted by
-   the endpoint, use the dashed IP address form.
+   the endpoint or pod name is longer than 63, use the dashed IP address form.
 * `ttl` allows you to set a custom TTL for responses. The default is 5 seconds.  The minimum TTL allowed is
   0 seconds, and the maximum is capped at 3600 seconds. Setting TTL to 0 will prevent records from being cached.
 * `noendpoints` will turn off the serving of endpoint records by disabling the watch on endpoints.

plugin/kubernetes/object/endpoint.go

@@ -136,7 +136,8 @@ func EndpointSliceToEndpoints(obj meta.Object) (meta.Object, error) {
 			if end.Hostname != nil {
 				ea.Hostname = *end.Hostname
 			}
-			if end.TargetRef != nil {
+			// ignore pod names that are too long to be a valid label
+			if end.TargetRef != nil && len(end.TargetRef.Name) < 64 {
 				ea.TargetRefName = end.TargetRef.Name
 			}
 			if end.NodeName != nil {
@@ -186,7 +187,8 @@ func EndpointSliceV1beta1ToEndpoints(obj meta.Object) (meta.Object, error) {
 			if end.Hostname != nil {
 				ea.Hostname = *end.Hostname
 			}
-			if end.TargetRef != nil {
+			// ignore pod names that are too long to be a valid label
+			if end.TargetRef != nil && len(end.TargetRef.Name) < 64 {
 				ea.TargetRefName = end.TargetRef.Name
 			}
 			// EndpointSlice does not contain NodeName, leave blank