Fix podgroup not creating Bug

pkg/controllers/podgroup/pg_controller_handler.go

@@ -78,7 +78,11 @@ func (pg *pgcontroller) addReplicaSet(obj interface{}) {
 		if err != nil && !apierrors.IsNotFound(err) {
 			klog.Errorf("Failed to delete PodGroup <%s/%s>: %v", rs.Namespace, pgName, err)
 		}
-	} else if *rs.Spec.Replicas > 0 {
+	}
+
+	// In the rolling upgrade scenario, the addReplicasSet(replicas=0) event may be received before
+	// the updateReplicaSet(replicas=1) event. In this event, need to create PodGroup for the pod.
+	if *rs.Spec.Replicas > 0 {
 		selector := metav1.LabelSelector{MatchLabels: rs.Spec.Selector.MatchLabels}
 		podList, err := pg.kubeClient.CoreV1().Pods(rs.Namespace).List(context.TODO(),
 			metav1.ListOptions{LabelSelector: metav1.FormatLabelSelector(&selector)})