MySQL 8.4 Reference Manual Including MySQL NDB Cluster 8.4
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 [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.
All options that can be used with ndb_mgm are shown in the following table. Additional descriptions follow the table.
--backup-password-from-stdin[=TRUE|FALSE]
| Command-Line Format | --backup-password-from-stdin |
|---|
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 |
|---|
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.
--execute=,
command-e
command
| 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 in the management
client:
$>ndb_mgm -e "SHOW"$>ndb_mgm --execute="SHOW"
This is analogous to how the
--execute or
-e option works with the
mysql command-line client. See
Section 6.2.2.1, “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 | --no-login-paths |
|---|
Skips reading options from the login path 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:].
Overrides entries in portNDB_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-mgm-tls=level |
|---|---|
| Type | Enumeration |
| Default Value | relaxed |
| Valid Values |
|
Sets the level of TLS support required to connect to the
management server; one of relaxed or
strict. relaxed (the
default) means that a TLS connection is attempted, but
success is not required; strict means
that TLS is required to connect.
| 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 | --ndb-tls-search-path=list |
|---|---|
| Type | Path name |
| Default Value (Unix) | $HOME/ndb-tls |
| Default Value (Windows) | $HOMEDIR/ndb-tls |
Specify a list of directories to search for a CA file. On
Unix platforms, the directory names are separated by colons
(:); on Windows systems, the semicolon
character (;) is used as the separator. A
directory reference may be relative or absolute; it may
contain one or more environment variables, each denoted by a
prefixed dollar sign ($), and expanded
prior to use.
Searching begins with the leftmost named directory and
proceeds from left to right until a file is found. An empty
string denotes an empty search path, which causes all
searches to fail. A string consisting of a single dot
(.) indicates that the search path
limited to the current working directory.
If no search path is supplied, the compiled-in default value
is used. This value depends on the platform used: On
Windows, this is \ndb-tls; on other
platforms (including Linux), it is
$HOME/ndb-tls. This can be overridden by
compiling NDB Cluster using
-DWITH_NDB_TLS_SEARCH_PATH.
| Command-Line Format | --no-defaults |
|---|
Do not read default options from any option file other than login file.
| Command-Line Format | --print-defaults |
|---|
Print program argument list and exit.
| Command-Line Format | --test-tls |
|---|
Connect using TLS, then exit. Output if successful is similar to what is shown here:
>$ ndb_mgm --test-tls
Connected to Management Server at: sakila:1186
>$
See Section 25.6.19.5, “TLS Link Encryption for NDB Cluster”, for more information.
| 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 25.6.1, “Commands in the NDB Cluster Management Client”.