MySQL 8.0 FAQ: NDB Cluster is to provide redundancy; the management node must run on a separate machine to guarantee continued arbitration services in the event that one of the data nodes fails. To provide increased throughput and high availability, you should use multiple SQL nodes (MySQL Servers connected to the cluster). It is also possible (although not strictly necessary) to run multiple management servers. An NDB Cluster has both a physical and logical organization, with computers being the physical elements. The logical or functional elements of a cluster are referred to as  nodes , and a computer housing a cluster node is sometimes referred to as a  cluster host . There are three types of nodes, each corresponding to a specific role within the cluster. These are: An  API node  is any application that makes direct use of Cluster data nodes for data storage and retrieval. An SQL node can thus be considered a type of API node that uses a MySQL Server to provide an SQL interface to the Cluster. You can write such applications (that do not depend on a MySQL Server) using the NDB API, which supplies a direct, object- oriented transaction and scanning interface to NDB Cluster data; see NDB Cluster API Overview: The NDB API, for more information. What does the  *  mean? How is this node different from the others? The simplest answer is, “It’s not something you can control, and it’s nothing that you need to worry about in any case, unless you’re a software engineer writing or analyzing the NDB Cluster source code” . If you don’t find that answer satisfactory, here’s a longer and more technical version: A number of mechanisms in NDB Cluster require distributed coordination among the data nodes. These distributed algorithms and protocols include global checkpointing, DDL (schema) changes, and node restart handling. To make this coordination simpler, the data nodes “elect”  one of their A.10.7. When I run the  SHOW  command in the NDB Cluster management client, I see a line of output that looks like this: • Management node.   This node provides management services for the cluster as a whole, including startup, shutdown, backups, and configuration data for the other nodes. The management node server is implemented as the application  ndb_mgmd ; the management client used to control NDB Cluster is  ndb_mgm . See Section 23.4.4, “ndb_mgmd — The NDB Cluster Management Server Daemon” , and Section 23.4.5, “ndb_mgm — The NDB Cluster Management Client” , for information about these programs. • Data node.   This type of node stores and replicates data. Data node functionality is handled by instances of the  NDB  data node process  ndbd . For more information, see Section 23.4.1, “ndbd — The NDB Cluster Data Node Daemon” . • SQL node.   This is simply an instance of MySQL Server ( mysqld ) that is built with support for the  NDBCLUSTER  storage engine and started with the  --ndb-cluster  option to enable the engine and the  --ndb-connectstring  option to enable it to connect to an NDB Cluster management server. For more about these options, see MySQL Server Options for NDB Cluster. A.10.6. What do the different computers do in an NDB Cluster? Note id=2 @10.100.10.32 (Version: 8.0.26-ndb-8.0.26 Nodegroup: 0, *) 5247