MySQL 8.4 Release Notes
This section describes how to add NDB Cluster data nodes “online”—that is, without needing to shut down the cluster completely and restart it as part of the process.
Important
目前,必须将新数据节点作为新节点组的一部分添加到 NDB 集群中。此外,无法在在线状态下更改分片副本的数量(或每个节点组的节点数)。Currently, you must add new data nodes to an NDB Cluster as part of a new node group. In addition, it is not possible to change the number of fragment replicas (or the number of nodes per node group) online.