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:
shell> ndb_mgm [host_name [port_num]]
shell> ndb_mgm ndb_mgmd.mysql.com 1186
The default host name and port number are
localhost and 1186, respectively.
The following table includes options that are specific to the NDB Cluster management client program ndb_mgm. Additional descriptions follow the table. For options common to most NDB Cluster programs (including ndb_mgm), see Section 6.29, “Options Common to NDB Cluster Programs — Options Common to NDB Cluster Programs”.
Table 6.4 Command-line options for the ndb_mgm program
|Format||Description||Added, Deprecated, or Removed|
|Set number of times to retry connection before giving up; 0 means 1 attempt only (and no retries)||
ADDED: NDB 7.4.9
|Set number of times to retry connection before giving up; synonym for --connect-retries||
DEPRECATED: NDB 7.4.9
|Execute command and exit||
(Supported in all MySQL 5.6 based releases)
Introduced 5.6.28-ndb-7.4.9 Type Numeric Default Value
This option specifies the number of times following the first attempt to retry a connection before giving up (the client always tries the connection at least once). The length of time to wait per attempt is set using
This option was added in NDB 7.4.9, and is synonymous with the
--try-reconnectoption, which is now deprecated.
The default for this option this option differs from its default when used with other
NDBprograms. See Section 6.29, “Options Common to NDB Cluster Programs — Options Common to NDB Cluster Programs”, for more information.
This option can be used to send a command to the NDB Cluster management client from the system shell. For example, either of the following is equivalent to executing
SHOWin the management client:
shell> ndb_mgm -e "SHOW" shell> ndb_mgm --execute="SHOW"Note
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.
Deprecated 5.6.28-ndb-7.4.9 Type Integer Default Value
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
numberbefore giving up and reporting an error instead.
This option is deprecated in NDB 7.4.9 and later, and is superseded by
Additional information about using ndb_mgm can be found in Section 7.1, “Commands in the NDB Cluster Management Client”.