The ndb_mgm management client process is actually not needed to run the cluster. Its value lies in providing a set of commands for checking the cluster's status, starting backups, and performing other administrative functions. The management client accesses the management server using a C API. Advanced users can also employ this API for programming dedicated management processes to perform tasks similar to those performed by ndb_mgm.
To start the management client, it is necessary to supply the host name and port number of the management server:
ndb_mgm ndb_mgmd.mysql.com 1186
The default host name and port number are
localhost and 1186, respectively. (Prior to
MySQL 4.1.8, the default Cluster port was 2200.)
The following table includes command options specific to the MySQL Cluster management client program ndb_mgm. Additional descriptions follow the table. For options common to all MySQL Cluster programs, see Section 15.4.20, “Options Common to MySQL Cluster Programs — Options Common to MySQL Cluster Programs”.
Table 15.11. ndb_mgm Command Line Options
This option can be used to send a command to the MySQL Cluster management client from the system shell. For example, either of the following:
ndb_mgm -e "SHOW"
is equivalent to
This is analogous to how the
-e option works with the
mysql command-line client. See
Section 220.127.116.11, “Using Options on the Command Line”.
If the management client command to be passed using this option contains any space characters, then the command must be enclosed in quotation marks. Either single or double quotation marks may be used. If the management client command contains no space characters, the quotation marks are optional.
If the connection to the management server is broken, the
node tries to reconnect to it every 5 seconds until it
succeeds. By using this option, it is possible to limit the
number of attempts to
before giving up and reporting an error instead.
Additional information about using ndb_mgm can be found in Section 15.5.2, “Commands in the MySQL Cluster Management Client”.