Nevermind, figured it out! See below for problem and solution. I'm following the tutorial on setting up a load balanced MySQL cluster on 4 machines. So far, I have the management server set up, and I have the 2 data nodes set up. Here's the problem: ndb_mgm> show; Connected to Management Server at: localhost:1186 Cluster Configuration --------------------- [ndbd(NDB)] 2 node(s) id=2 @xxx.xxx.xxx.242 (Version: 5.0.45, starting, Nodegroup: 0) id=3 @xxx.xxx.xxx.243 (Version: 5.0.45, starting, Nodegroup: 0) [ndb_mgmd(MGM)] 1 node(s) id=1 (Version: 5.0.45) [mysqld(API)] 2 node(s) id=4 (not connected, accepting connect from any host) id=5 (not connected, accepting connect from any host) but it SHOULD be this: ndb_mgm> show; Connected to Management Server at: localhost:1186 Cluster Configuration --------------------- [ndbd(NDB)] 2 node(s) id=2 @xxx.xxx.xxx.242 (Version: 5.0.45, Nodegroup: 0, Master) id=3 @xxx.xxx.xxx.243 (Version: 5.0.45, Nodegroup: 0) [ndb_mgmd(MGM)] 1 node(s) id=1 @xxx.xxx.xxx.241 (Version: 5.0.45) [mysqld(API)] 2 node(s) id=4 @xxx.xxx.xxx.242 (Version: 5.0.45) id=5 @xxx.xxx.xxx.243 (Version: 5.0.45) So, basically, my 2 data storage nodes are not connected in the mysqld section, but are connected in the ndbd section. My config.ini on the management server is: [ndbd default] NoOfReplicas=2 [mysqld default] [ndb_mgmd default] [tcp default] # Section for the cluster management node [ndb_mgmd] # IP address of the management node (this system) HostName=216.147.203.241 # Section for the storage nodes [ndbd] # IP address of the first storage node HostName=216.147.203.242 DataDir=/var/lib/mysql-cluster [ndbd] # IP address of the second storage node HostName=216.147.203.243 DataDir=/var/lib/mysql-cluster # one [MYSQLD] per storage node [mysqld] HostName=216.147.203.242 [mysqld] HostName=216.147.203.243 I also tried it without explicitly listing the hosts in the mysqld sections above, but that produced the same results. Both of my data nodes have the following /etc/my.cnf: [mysqld] ndbcluster ndb-connectstring=216.147.203.241 [mysql_cluster] ndb-connectstring=216.147.203.241 The problem turned out to be that one of the two storage nodes had a firewall which was preventing communication.