Fixing Potential Race Condition in EndpointSlice Controller.

This adds a new EndpointSlice tracker to keep track of the expected resource versions of EndpointSlices associated with each Service managed by the EndpointSlice controller. This should prevent a potential race where a syncService call could happen with an incomplete view of EndpointSlices if additions or deletions hadn't fully propagated to the cache yet. Additionally, this ensures that external changes to EndpointSlices will be handled by the EndpointSlice controller.

pkg/controller/endpointslice/reconciler.go

@@ -40,6 +40,7 @@ type reconciler struct {
 	client               clientset.Interface
 	nodeLister           corelisters.NodeLister
 	maxEndpointsPerSlice int32
+	endpointSliceTracker *endpointSliceTracker
 	metricsCache         *metrics.Cache
 }
 
@@ -212,6 +213,7 @@ func (r *reconciler) finalize(
 			}
 			errs = append(errs, fmt.Errorf("Error creating EndpointSlice for Service %s/%s: %v", service.Namespace, service.Name, err))
 		} else {
+			r.endpointSliceTracker.Update(endpointSlice)
 			metrics.EndpointSliceChanges.WithLabelValues("create").Inc()
 		}
 	}
@@ -222,6 +224,7 @@ func (r *reconciler) finalize(
 		if err != nil {
 			errs = append(errs, fmt.Errorf("Error updating %s EndpointSlice for Service %s/%s: %v", endpointSlice.Name, service.Namespace, service.Name, err))
 		} else {
+			r.endpointSliceTracker.Update(endpointSlice)
 			metrics.EndpointSliceChanges.WithLabelValues("update").Inc()
 		}
 	}
@@ -231,6 +234,7 @@ func (r *reconciler) finalize(
 		if err != nil {
 			errs = append(errs, fmt.Errorf("Error deleting %s EndpointSlice for Service %s/%s: %v", endpointSlice.Name, service.Namespace, service.Name, err))
 		} else {
+			r.endpointSliceTracker.Delete(endpointSlice)
 			metrics.EndpointSliceChanges.WithLabelValues("delete").Inc()
 		}
 	}