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]]
For example:
shell> ndb_mgm ndb_mgmd.mysql.com 1186
The default host name and port number are localhost and 1186, respectively.
All options that can be used with ndb_mgm are shown in the following table. Additional descriptions follow the table.
Table 23.27 Command-line options used with the program ndb_mgm
| Format | Description | Added, Deprecated, or Removed |
|---|---|---|
| Get decryption password in a secure fashion from STDIN; use together with --execute and START BACKUP command | ADDED: NDB 8.0.24 |
|
| Directory containing character sets | (Supported in all NDB releases based on MySQL 8.0) |
|
| Set number of times to retry connection before giving up; 0 means 1 attempt only (and no retries) | (Supported in all NDB releases based on MySQL 8.0) |
|
| Number of seconds to wait between attempts to contact management server | (Supported in all NDB releases based on MySQL 8.0) |
|
| Same as --ndb-connectstring | (Supported in all NDB releases based on MySQL 8.0) |
|
| Write core file on error; used in debugging | (Supported in all NDB releases based on MySQL 8.0) |
|
| Read given file after global files are read | (Supported in all NDB releases based on MySQL 8.0) |
|
| Read default options from given file only | (Supported in all NDB releases based on MySQL 8.0) |
|
| Also read groups with concat(group, suffix) | (Supported in all NDB releases based on MySQL 8.0) |
|
| Cause START BACKUP to encrypt whenever making a backup, prompting for password if not supplied by user | ADDED: NDB 8.0.24 |
|
| Execute command and exit | (Supported in all NDB releases based on MySQL 8.0) |
|
| Display help text and exit | (Supported in all NDB releases based on MySQL 8.0) |
|
| Read given path from login file | (Supported in all NDB releases based on MySQL 8.0) |
|
| Set connect string for connecting to ndb_mgmd. Syntax: "[nodeid=id;][host=]hostname[:port]". Overrides entries in NDB_CONNECTSTRING and my.cnf | (Supported in all NDB releases based on MySQL 8.0) |
|
| Same as --ndb-connectstring | (Supported in all NDB releases based on MySQL 8.0) |
|
| Set node ID for this node, overriding any ID set by --ndb-connectstring | (Supported in all NDB releases based on MySQL 8.0) |
|
| Enable optimizations for selection of nodes for transactions. Enabled by default; use --skip-ndb-optimized-node-selection to disable | (Supported in all NDB releases based on MySQL 8.0) |
|
| Do not read default options from any option file other than login file | (Supported in all NDB releases based on MySQL 8.0) |
|
| Print program argument list and exit | (Supported in all NDB releases based on MySQL 8.0) |
|
| Set number of times to retry connection before giving up; synonym for --connect-retries | (Supported in all NDB releases based on MySQL 8.0) |
|
| Display help text and exit; same as --help | (Supported in all NDB releases based on MySQL 8.0) |
|
| Display version information and exit | (Supported in all NDB releases based on MySQL 8.0) |
--backup-password-from-stdin[=TRUE|FALSE]
| Command-Line Format | --backup-password-from-stdin[=value] |
|---|---|
| Introduced | 8.0.24-ndb-8.0.24 |
| Type | Boolean |
| Default Value | FALSE |
This option enables input of the backup password from the system shell (stdin) when using --execute "START BACKUP" or similar to create a backup. Use of this option requires use of --execute as well.
| Command-Line Format | --character-sets-dir=path |
|---|
Directory containing character sets.
| Command-Line Format | --connect-retries=# |
|---|---|
| Type | Numeric |
| Default Value | 3 |
| Minimum Value | 0 |
| Maximum Value | 4294967295 |
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 --connect-retry-delay.
This option is synonymous with the --try-reconnect option, which is now deprecated.
| Command-Line Format | --connect-retry-delay=# |
|---|---|
| Type | Integer |
| Default Value | 5 |
| Minimum Value | 0 |
| Maximum Value | 5 |
Number of seconds to wait between attempts to contact management server.
| Command-Line Format | --connect-string=connection-string |
|---|---|
| Type | String |
| Default Value | [none] |
Same as --ndb-connectstring.
| Command-Line Format | --core-file |
|---|
Write core file on error; used in debugging.
| Command-Line Format | --defaults-extra-file=path |
|---|---|
| Type | String |
| Default Value | [none] |
Read given file after global files are read.
| Command-Line Format | --defaults-file=path |
|---|---|
| Type | String |
| Default Value | [none] |
Read default options from given file only.
| Command-Line Format | --defaults-group-suffix=string |
|---|---|
| Type | String |
| Default Value | [none] |
Also read groups with concat(group, suffix).
| Command-Line Format | --encrypt-backup[=TRUE|FALSE] |
|---|---|
| Introduced | 8.0.24-ndb-8.0.24 |
| Type | Boolean |
| Default Value | TRUE |
When used, this option causes all backups to be encrypted. To make this happen whenever ndb_mgm is run, put the option in the [ndb_mgm] section of the my.cnf file.
| Command-Line Format | --execute=name |
|---|
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 SHOW in the management client:
shell>ndb_mgm -e "SHOW"shell>ndb_mgm --execute="SHOW"
This is analogous to how the --execute or -e option works with the mysql command-line client. See Section 4.2.2.1, “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.
| Command-Line Format | --help |
|---|
Display help text and exit.
| Command-Line Format | --login-path=path |
|---|---|
| Type | String |
| Default Value | [none] |
Read given path from login file.
| Command-Line Format | --ndb-connectstring=connection-string |
|---|---|
| Type | String |
| Default Value | [none] |
Set connect string for connecting to ndb_mgmd. Syntax: "[nodeid=id;][host=]hostname[:port]". Overrides entries in NDB_CONNECTSTRING and my.cnf.
| Command-Line Format | --ndb-nodeid=# |
|---|---|
| Type | Integer |
| Default Value | [none] |
Set node ID for this node, overriding any ID set by --ndb-connectstring.
| Command-Line Format | --ndb-mgmd-host=connection-string |
|---|---|
| Type | String |
| Default Value | [none] |
Same as --ndb-connectstring.
--ndb-optimized-node-selection
| Command-Line Format | --ndb-optimized-node-selection |
|---|
Enable optimizations for selection of nodes for transactions. Enabled by default; use --skip-ndb-optimized-node-selection to disable.
| Command-Line Format | --no-defaults |
|---|
Do not read default options from any option file other than login file.
| Command-Line Format | --print-defaults |
|---|
Print program argument list and exit.
| Command-Line Format | --try-reconnect=# |
|---|---|
| Deprecated | Yes |
| Type | Numeric |
| Type | Integer |
| Default Value | 12 |
| Default Value | 3 |
| Minimum Value | 0 |
| Maximum Value | 4294967295 |
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 number before giving up and reporting an error instead.
This option is deprecated and subject to removal in a future release. Use --connect-retries, instead.
| Command-Line Format | --usage |
|---|
Display help text and exit; same as --help.
| Command-Line Format | --version |
|---|
Display version information and exit.
Additional information about using ndb_mgm can be found in Section 23.5.1, “Commands in the NDB Cluster Management Client”.