fix: add delay to backup trigger invocation

- Introduce a sleep command before triggering backup for each pod
- This change prevents simultaneous execution of backup tasks
- Ensures system stability by spreading out resource usage during backups

backups/daemonset+cronjob/crontab.yaml

@@ -26,6 +26,7 @@ spec:
               # 创建触发文件到所有备份 Pod 中
               for pod in $(kubectl get pods -n backup-system -l app=node-backup -o jsonpath='{.items[*].metadata.name}'); do
                 echo "触发 Pod $pod 执行备份"
+                sleep 60
                 kubectl exec $pod -n backup-system -- touch /tmp/backup-triggered
               done
               echo "所有节点备份已触发"