For our four-node, four-host NDB Cluster, it is necessary to write four configuration files, one per node host.
Each data node or SQL node requires a
my.cnffile that provides two pieces of information: a connection string that tells the node where to find the management node, and a line telling the MySQL server on this host (the machine hosting the data node) to enable the
For more information on connection strings, see Section 5.3.3, “NDB Cluster Connection Strings”.
The management node needs a
config.inifile telling it how many replicas to maintain, how much memory to allocate for data and indexes on each data node, where to find the data nodes, where to save data to disk on each data node, and where to find any SQL nodes.
Configuring the data nodes and SQL nodes.
my.cnf file needed for the data nodes
is fairly simple. The configuration file should be located in
/etc directory and can be edited using
any text editor. (Create the file if it does not exist.) For
shell> vi /etc/my.cnf
We show vi being used here to create the file, but any text editor should work just as well.
For each data node and SQL node in our example setup,
my.cnf should look like this:
[mysqld] # Options for mysqld process: ndbcluster # run NDB storage engine [mysql_cluster] # Options for NDB Cluster processes: ndb-connectstring=198.51.100.10 # location of management server
After entering the preceding information, save this file and exit the text editor. Do this for the machines hosting data node “A”, data node “B”, and the SQL node.
Once you have started a mysqld process with
ndb-connectstring parameters in the
[mysql_cluster] sections of the
my.cnf file as shown previously, you cannot
CREATE TABLE or
ALTER TABLE statements without
having actually started the cluster. Otherwise, these statements
will fail with an error. This is by design.
Configuring the management node.
The first step in configuring the management node is to create
the directory in which the configuration file can be found and
then to create the file itself. For example (running as
shell> mkdir /var/lib/mysql-cluster shell> cd /var/lib/mysql-cluster shell> vi config.ini
For our representative setup, the
file should read as follows:
[ndbd default] # Options affecting ndbd processes on all data nodes: NoOfReplicas=2 # Number of replicas DataMemory=80M # How much memory to allocate for data storage IndexMemory=18M # How much memory to allocate for index storage # For DataMemory and IndexMemory, we have used the # default values. Since the "world" database takes up # only about 500KB, this should be more than enough for # this example Cluster setup. [tcp default] # TCP/IP options: PortNumber=2202 # This the default; however, you can use any # port that is free for all the hosts in the cluster # Note: It is recommended that you do not specify the port # number at all and simply allow the default value to be used # instead [ndb_mgmd] # Management process options: HostName=198.51.100.10 # Hostname or IP address of MGM node DataDir=/var/lib/mysql-cluster # Directory for MGM node log files [ndbd] # Options for data node "A": # (one [ndbd] section per data node) HostName=198.51.100.30 # Hostname or IP address NodeId=2 # Node ID for this data node DataDir=/usr/local/mysql/data # Directory for this data node's data files [ndbd] # Options for data node "B": HostName=198.51.100.40 # Hostname or IP address NodeId=3 # Node ID for this data node DataDir=/usr/local/mysql/data # Directory for this data node's data files [mysqld] # SQL node options: HostName=198.51.100.20 # Hostname or IP address # (additional mysqld connections can be # specified for this node for various # purposes such as running ndb_restore)
world database can be downloaded from
After all the configuration files have been created and these minimal options have been specified, you are ready to proceed with starting the cluster and verifying that all processes are running. We discuss how this is done in Section 4.4, “Initial Startup of NDB Cluster”.
For more detailed information about the available NDB Cluster configuration parameters and their uses, see Section 5.3, “NDB Cluster Configuration Files”, and Chapter 5, Configuration of NDB Cluster. For configuration of NDB Cluster as relates to making backups, see Section 7.3.3, “Configuration for NDB Cluster Backups”.
The default port for Cluster management nodes is 1186; the default port for data nodes is 2202. However, the cluster can automatically allocate ports for data nodes from those that are already free.