### 23.5.5 ndb\_mgm — The NDB Cluster Management Client

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 The [**ndb\_mgm**](mysql-cluster-programs-ndb-mgm.html) 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**](mysql-cluster-programs-ndb-mgm.html).

 To start the management client, it is necessary to supply the host name and port number of the management server:

```
$> ndb_mgm [host_name [port_num]]
```

 For example:

```
$> ndb_mgm ndb_mgmd.mysql.com 1186
```

 The default host name and port number are `localhost` and 1186, respectively.

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 All options that can be used with [**ndb\_mgm**](mysql-cluster-programs-ndb-mgm.html) are shown in the following table. Additional descriptions follow the table.

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**Table 23.27 Command-line options used with the program ndb\_mgm**

|                                                                                                          Format                                                                                                          |                                                                  Description                                                                   |           Added, Deprecated, or Removed           |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------|
|                                                    ` [--backup-password-from-stdin](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_backup-password-from-stdin) `                                                     |             Get decryption password in a secure fashion from STDIN; use together with --execute and ndb\_mgm START BACKUP command              |                 ADDED: NDB 8.0.24                 |
|                                                          ` [--character-sets-dir=path](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_character-sets-dir) `                                                          |                                                      Directory containing character sets                                                       | (Supported in all NDB releases based on MySQL 8.0)|
|                                                              ` [--connect-retries=#](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_connect-retries) `                                                               |                       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)|
|                                                          ` [--connect-retry-delay=#](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_connect-retry-delay) `                                                           |                                    Number of seconds to wait between attempts to contact management server                                     | (Supported in all NDB releases based on MySQL 8.0)|
|    `[--connect-string=connection_string](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_connect-string)`,<br/><br/>` [-c connection_string](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_connect-string) `     |                                                          Same as --ndb-connectstring                                                           | (Supported in all NDB releases based on MySQL 8.0)|
|                                                                     ` [--core-file](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_core-file) `                                                                      |                                                  Write core file on error; used in debugging                                                   | (Supported in all NDB releases based on MySQL 8.0)|
|                                                         ` [--defaults-extra-file=path](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_defaults-extra-file) `                                                         |                                                  Read given file after global files are read                                                   | (Supported in all NDB releases based on MySQL 8.0)|
|                                                               ` [--defaults-file=path](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_defaults-file) `                                                               |                                                   Read default options from given file only                                                    | (Supported in all NDB releases based on MySQL 8.0)|
|                                                      ` [--defaults-group-suffix=string](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_defaults-group-suffix) `                                                      |                                                  Also read groups with concat(group, suffix)                                                   | (Supported in all NDB releases based on MySQL 8.0)|
|                                                                ` [--encrypt-backup](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_encrypt-backup) `                                                                 |                     Cause START BACKUP to encrypt whenever making a backup, prompting for password if not supplied by user                     |                 ADDED: NDB 8.0.24                 |
|                         `[--execute=command](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_execute)`,<br/><br/>` [-e command](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_execute) `                         |                                                            Execute command and exit                                                            | (Supported in all NDB releases based on MySQL 8.0)|
|                                     `[--help](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_help)`,<br/><br/>` [-?](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_help) `                                      |                                                           Display help text and exit                                                           | (Supported in all NDB releases based on MySQL 8.0)|
|                                                                  ` [--login-path=path](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_login-path) `                                                                  |                                                        Read given path from login file                                                         | (Supported in all NDB releases based on MySQL 8.0)|
|`[--ndb-connectstring=connection_string](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_ndb-connectstring)`,<br/><br/>` [-c connection_string](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_ndb-connectstring) `|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)|
|      `[--ndb-mgmd-host=connection_string](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_ndb-mgmd-host)`,<br/><br/>` [-c connection_string](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_ndb-mgmd-host) `      |                                                          Same as --ndb-connectstring                                                           | (Supported in all NDB releases based on MySQL 8.0)|
|                                                                   ` [--ndb-nodeid=#](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_ndb-nodeid) `                                                                    |                                    Set node ID for this node, overriding any ID set by --ndb-connectstring                                     | (Supported in all NDB releases based on MySQL 8.0)|
|                                                  ` [--ndb-optimized-node-selection](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_ndb-optimized-node-selection) `                                                   |      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)|
|                                                                   ` [--no-defaults](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_no-defaults) `                                                                    |                                     Do not read default options from any option file other than login file                                     | (Supported in all NDB releases based on MySQL 8.0)|
|                                                                ` [--print-defaults](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_print-defaults) `                                                                 |                                                      Print program argument list and exit                                                      | (Supported in all NDB releases based on MySQL 8.0)|
|                      `[--try-reconnect=#](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_try-reconnect)`,<br/><br/>` [-t #](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_try-reconnect) `                      |                            Set number of times to retry connection before giving up; synonym for --connect-retries                             | (Supported in all NDB releases based on MySQL 8.0)|
|                                    `[--usage](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_usage)`,<br/><br/>` [-?](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_usage) `                                    |                                                   Display help text and exit; same as --help                                                   | (Supported in all NDB releases based on MySQL 8.0)|
|                                 `[--version](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_version)`,<br/><br/>` [-V](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_version) `                                 |                                                      Display version information and exit                                                      | (Supported in all NDB releases based on MySQL 8.0)|

* []() `--backup-password-from-stdin[=TRUE|FALSE]`

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  |Command-Line Format|`--backup-password-from-stdin`|
  |-------------------|------------------------------|
  |    Introduced     |      8.0.24-ndb-8.0.24       |

   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`](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_execute) as well.

* []() `--character-sets-dir`

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  |Command-Line Format|`--character-sets-dir=path`|
  |-------------------|---------------------------|

   Directory containing character sets.

* []() `--connect-retries=*`#`*`

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  |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`](mysql-cluster-programs-ndb-mgmd.html#option_ndb_mgmd_connect-retry-delay).

   This option is synonymous with the [`--try-reconnect`](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_try-reconnect) option, which is now deprecated.

* []() `--connect-retry-delay`

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  |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.

* []() `--connect-string`

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  |Command-Line Format|`--connect-string=connection_string`|
  |-------------------|------------------------------------|
  |       Type        |               String               |
  |   Default Value   |              `[none]`              |

   Same as [`--ndb-connectstring`](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_ndb-connectstring).

* []() `--core-file`

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  |Command-Line Format|`--core-file`|
  |-------------------|-------------|

   Write core file on error; used in debugging.

* []() `--defaults-extra-file`

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  |Command-Line Format|`--defaults-extra-file=path`|
  |-------------------|----------------------------|
  |       Type        |           String           |
  |   Default Value   |          `[none]`          |

   Read given file after global files are read.

* []() `--defaults-file`

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  |Command-Line Format|`--defaults-file=path`|
  |-------------------|----------------------|
  |       Type        |        String        |
  |   Default Value   |       `[none]`       |

   Read default options from given file only.

* []() `--defaults-group-suffix`

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  |Command-Line Format|`--defaults-group-suffix=string`|
  |-------------------|--------------------------------|
  |       Type        |             String             |
  |   Default Value   |            `[none]`            |

   Also read groups with concat(group, suffix).

* []() `--encrypt-backup`

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  |Command-Line Format|`--encrypt-backup`|
  |-------------------|------------------|
  |    Introduced     |8.0.24-ndb-8.0.24 |

   When used, this option causes all backups to be encrypted. To make this happen whenever [**ndb\_mgm**](mysql-cluster-programs-ndb-mgm.html) is run, put the option in the `[ndb_mgm]` section of the `my.cnf` file.

* []() `--execute=`command``, `-e `command``

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  |Command-Line Format|`--execute=command`|
  |-------------------|-------------------|

   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`](mysql-cluster-mgm-client-commands.html#ndbclient-show) in the management client:

  ```
  $> ndb_mgm -e "SHOW"

  $> ndb_mgm --execute="SHOW"
  ```

   This is analogous to how the [`--execute`](mysql-command-options.html#option_mysql_execute) or `-e` option works with the [**mysql**](mysql.html) command-line client. See [Section 4.2.2.1, “Using Options on the Command Line”](command-line-options.html).

  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.

* []() `--help`

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  |Command-Line Format|`--help`|
  |-------------------|--------|

   Display help text and exit.

* []() `--login-path`

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  |Command-Line Format|`--login-path=path`|
  |-------------------|-------------------|
  |       Type        |      String       |
  |   Default Value   |     `[none]`      |

   Read given path from login file.

* []() `--ndb-connectstring`

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  |Command-Line Format|`--ndb-connectstring=connection_string`|
  |-------------------|---------------------------------------|
  |       Type        |                String                 |
  |   Default Value   |               `[none]`                |

   Set connect string for connecting to [**ndb\_mgmd**](mysql-cluster-programs-ndb-mgmd.html). Syntax: [`nodeid=*`id`*;`][`host=`]`*`hostname`*`[`:*`port`*`]. Overrides entries in `NDB_CONNECTSTRING` and `my.cnf`.

* []() `--ndb-nodeid`

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  |Command-Line Format|`--ndb-nodeid=#`|
  |-------------------|----------------|
  |       Type        |    Integer     |
  |   Default Value   |    `[none]`    |

   Set node ID for this node, overriding any ID set by [`--ndb-connectstring`](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_ndb-connectstring).

* []() `--ndb-mgmd-host`

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  |Command-Line Format|`--ndb-mgmd-host=connection_string`|
  |-------------------|-----------------------------------|
  |       Type        |              String               |
  |   Default Value   |             `[none]`              |

   Same as [`--ndb-connectstring`](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_ndb-connectstring).

* []() `--ndb-optimized-node-selection`

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  |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.

* []() `--no-defaults`

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  |Command-Line Format|`--no-defaults`|
  |-------------------|---------------|

   Do not read default options from any option file other than login file.

* []() `--print-defaults`

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  |Command-Line Format|`--print-defaults`|
  |-------------------|------------------|

   Print program argument list and exit.

* []() `--try-reconnect=*`number`*`

  |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`](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_connect-retries), instead.

* []() `--usage`

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  |Command-Line Format|`--usage`|
  |-------------------|---------|

   Display help text and exit; same as [`--help`](mysql-cluster-programs-ndb-mgm.html#option_ndb_mgm_help).

* []() `--version`

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  |Command-Line Format|`--version`|
  |-------------------|-----------|

   Display version information and exit.

 Additional information about using [**ndb\_mgm**](mysql-cluster-programs-ndb-mgm.html) can be found in [Section 23.6.1, “Commands in the NDB Cluster Management Client”](mysql-cluster-mgm-client-commands.html).

