This tool extracts current configuration information for data nodes, SQL nodes, and API nodes from one of a number of sources: an NDB Cluster management node, or its config.ini or my.cnf file. By default, the management node is the source for the configuration data; to override the default, execute ndb_config with the --config-file or --mycnf option. It is also possible to use a data node as the source by specifying its node ID with --config_from_node=.node_id
ndb_config can also provide an offline dump of all configuration parameters which can be used, along with their default, maximum, and minimum values and other information. The dump can be produced in either text or XML format; for more information, see the discussion of the --configinfo and --xml options later in this section).
You can filter the results by section (DB, SYSTEM, or CONNECTIONS) using one of the options --nodes, --system, or --connections.
All options that can be used with ndb_config are shown in the following table. Additional descriptions follow the table.
Table 23.29 Command-line options used with the program ndb_config
| Format | Description | Added, Deprecated, or Removed |
|---|---|---|
| Directory containing character sets | (Supported in all NDB releases based on MySQL 8.0) |
|
| Override defaults group suffix when reading cluster_config sections in my.cnf file; used in testing | ADDED: NDB 8.0.24 |
|
| Set the path to config.ini file | (Supported in all NDB releases based on MySQL 8.0) |
|
| Obtain configuration data from the node having this ID (must be a data node) | (Supported in all NDB releases based on MySQL 8.0) |
|
| Dumps information about all NDB configuration parameters in text format with default, maximum, and minimum values. Use with --xml to obtain XML output | (Supported in all NDB releases based on MySQL 8.0) |
|
| Print connections information ([tcp], [tcp default], [sci], [sci default], [shm], or [shm default] sections of cluster configuration file) only. Cannot be used with --system or --nodes | (Supported in all NDB releases based on MySQL 8.0) |
|
| Number of times to retry connection before giving up | (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) |
|
| Print only configuration parameters that have non-default values | (Supported in all NDB releases based on MySQL 8.0) |
|
| Field separator | (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) |
|
| Specify host | (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) |
|
| Read configuration data from my.cnf 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) |
|
| Get configuration of node with this ID | (Supported in all NDB releases based on MySQL 8.0) |
|
| Print node information ([ndbd] or [ndbd default] section of cluster configuration file) only. Cannot be used with --system or --connections | (Supported in all NDB releases based on MySQL 8.0) |
|
| One or more query options (attributes) | (Supported in all NDB releases based on MySQL 8.0) |
|
| Dumps all parameters and values to a single comma-delimited string | (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) |
|
| Row separator | (Supported in all NDB releases based on MySQL 8.0) |
|
| Print SYSTEM section information only (see ndb_config --configinfo output). Cannot be used with --nodes or --connections | (Supported in all NDB releases based on MySQL 8.0) |
|
| Specify node type | (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) |
|
| Use --xml with --configinfo to obtain a dump of all NDB configuration parameters in XML format with default, maximum, and minimum values | (Supported in all NDB releases based on MySQL 8.0) |
| Command-Line Format | --cluster-config-suffix=name |
|---|---|
| Introduced | 8.0.24-ndb-8.0.24 |
| Type | String |
| Default Value | [none] |
Override defaults group suffix when reading cluster configuration sections in my.cnf; used in testing.
The --configinfo option causes ndb_config to dump a list of each NDB Cluster configuration parameter supported by the NDB Cluster distribution of which ndb_config is a part, including the following information:
A brief description of each parameter's purpose, effects, and usage
The section of the config.ini file where the parameter may be used
The parameter's data type or unit of measurement
Where applicable, the parameter's default, minimum, and maximum values
NDB Cluster release version and build information
By default, this output is in text format. Part of this output is shown here:
shell> ndb_config --configinfo
****** SYSTEM ******
Name (String)
Name of system (NDB Cluster)
MANDATORY
PrimaryMGMNode (Non-negative Integer)
Node id of Primary ndb_mgmd(MGM) node
Default: 0 (Min: 0, Max: 4294967039)
ConfigGenerationNumber (Non-negative Integer)
Configuration generation number
Default: 0 (Min: 0, Max: 4294967039)
****** DB ******
MaxNoOfSubscriptions (Non-negative Integer)
Max no of subscriptions (default 0 == MaxNoOfTables)
Default: 0 (Min: 0, Max: 4294967039)
MaxNoOfSubscribers (Non-negative Integer)
Max no of subscribers (default 0 == 2 * MaxNoOfTables)
Default: 0 (Min: 0, Max: 4294967039)
…
Use this option together with the --xml option to obtain output in XML format.
| Command-Line Format | --config-file=file_name |
|---|---|
| Type | File name |
| Default Value | |
Gives the path to the management server's configuration file (config.ini). This may be a relative or absolute path. If the management node resides on a different host from the one on which ndb_config is invoked, then an absolute path must be used.
| Command-Line Format | --config-from-node=# |
|---|---|
| Type | Numeric |
| Default Value | none |
| Minimum Value | 1 |
| Maximum Value | 48 |
Obtain the cluster's configuration data from the data node that has this ID.
If the node having this ID is not a data node, ndb_config fails with an error. (To obtain configuration data from the management node instead, simply omit this option.)
| Command-Line Format | --connections |
|---|---|
| Type | Boolean |
| Default Value | FALSE |
Tells ndb_config to print CONNECTIONS information only—that is, information about parameters found in the [tcp], [tcp default], [shm], or [shm default] sections of the cluster configuration file (see Section 23.3.3.10, “NDB Cluster TCP/IP Connections”, and Section 23.3.3.12, “NDB Cluster Shared-Memory Connections”, for more information).
This option is mutually exclusive with --nodes and --system; only one of these 3 options can be used.
| Command-Line Format | --diff-default |
|---|---|
| Type | Boolean |
| Default Value | FALSE |
Print only configuration parameters that have non-default values.
--fields=, delimiter-f delimiter
| Command-Line Format | --fields=string |
|---|---|
| Type | String |
| Default Value | |
Specifies a delimiter string used to separate the fields in the result. The default is , (the comma character).
If the delimiter contains spaces or escapes (such as \n for the linefeed character), then it must be quoted.
| Command-Line Format | --host=name |
|---|---|
| Type | String |
| Default Value | |
Specifies the host name of the node for which configuration information is to be obtained.
While the hostname localhost usually resolves to the IP address 127.0.0.1, this may not necessarily be true for all operating platforms and configurations. This means that it is possible, when localhost is used in config.ini, for ndb_config --host=localhost to fail if ndb_config is run on a different host where localhost resolves to a different address (for example, on some versions of SUSE Linux, this is 127.0.0.2). In general, for best results, you should use numeric IP addresses for all NDB Cluster configuration values relating to hosts, or verify that all NDB Cluster hosts handle localhost in the same fashion.
| Command-Line Format | --mycnf |
|---|---|
| Type | Boolean |
| Default Value | FALSE |
Read configuration data from the my.cnf file.
--ndb-connectstring=, connection_string-c connection_string
| Command-Line Format | --ndb-connectstring=connection-string |
|---|---|
| Type | String |
| Default Value | [none] |
Specifies the connection string to use in connecting to the management server. The format for the connection string is the same as described in Section 23.3.3.3, “NDB Cluster Connection Strings”, and defaults to localhost:1186.
| Command-Line Format | --no-defaults |
|---|
Do not read default options from any option file other than login file.
| Command-Line Format | --ndb-nodeid=# |
|---|---|
| Type | Integer |
| Default Value | [none] |
Specify the node ID of the node for which configuration information is to be obtained.
| Command-Line Format | --nodes |
|---|---|
| Type | Boolean |
| Default Value | FALSE |
Tells ndb_config to print information relating only to parameters defined in an [ndbd] or [ndbd default] section of the cluster configuration file (see Section 23.3.3.6, “Defining NDB Cluster Data Nodes”).
This option is mutually exclusive with --connections and --system; only one of these 3 options can be used.
--query=, query-options-q query-options
| Command-Line Format | --query=string |
|---|---|
| Type | String |
| Default Value | |
This is a comma-delimited list of query options—that is, a list of one or more node attributes to be returned. These include nodeid (node ID), type (node type—that is, ndbd, mysqld, or ndb_mgmd), and any configuration parameters whose values are to be obtained.
For example, --query=nodeid,type,datamemory,datadir returns the node ID, node type, DataMemory, and DataDir for each node.
If a given parameter is not applicable to a certain type of node, than an empty string is returned for the corresponding value. See the examples later in this section for more information.
| Command-Line Format | --query-all |
|---|---|
| Type | String |
| Default Value | |
Returns a comma-delimited list of all query options (node attributes; note that this list is a single string.
--rows=, separator-r separator
| Command-Line Format | --rows=string |
|---|---|
| Type | String |
| Default Value | |
Specifies a separator string used to separate the rows in the result. The default is a space character.
If the separator contains spaces or escapes (such as \n for the linefeed character), then it must be quoted.
| Command-Line Format | --system |
|---|---|
| Type | Boolean |
| Default Value | FALSE |
Tells ndb_config to print SYSTEM information only. This consists of system variables that cannot be changed at run time; thus, there is no corresponding section of the cluster configuration file for them. They can be seen (prefixed with ****** SYSTEM ******) in the output of ndb_config --configinfo.
This option is mutually exclusive with --nodes and --connections; only one of these 3 options can be used.
| Command-Line Format | --type=name |
|---|---|
| Type | Enumeration |
| Default Value | [none] |
| Valid Values |
|
Filters results so that only configuration values applying to nodes of the specified node_type (ndbd, mysqld, or ndb_mgmd) are returned.
| Command-Line Format | --help |
|---|
Causes ndb_config to print a list of available options, and then exit.
| Command-Line Format | --version |
|---|
Causes ndb_config to print a version information string, and then exit.
| Command-Line Format | --configinfo --xml |
|---|---|
| Type | Boolean |
| Default Value | false |
Cause ndb_config --configinfo to provide output as XML by adding this option. A portion of such output is shown in this example:
shell> ndb_config --configinfo --xml
<configvariables protocolversion="1" ndbversionstring="5.7.33-ndb-7.5.23"
ndbversion="460032" ndbversionmajor="7" ndbversionminor="5"
ndbversionbuild="0">
<section name="SYSTEM">
<param name="Name" comment="Name of system (NDB Cluster)" type="string"
mandatory="true"/>
<param name="PrimaryMGMNode" comment="Node id of Primary ndb_mgmd(MGM) node"
type="unsigned" default="0" min="0" max="4294967039"/>
<param name="ConfigGenerationNumber" comment="Configuration generation number"
type="unsigned" default="0" min="0" max="4294967039"/>
</section>
<section name="MYSQLD" primarykeys="NodeId">
<param name="wan" comment="Use WAN TCP setting as default" type="bool"
default="false"/>
<param name="HostName" comment="Name of computer for this node"
type="string" default=""/>
<param name="Id" comment="NodeId" type="unsigned" mandatory="true"
min="1" max="255" deprecated="true"/>
<param name="NodeId" comment="Number identifying application node (mysqld(API))"
type="unsigned" mandatory="true" min="1" max="255"/>
<param name="ExecuteOnComputer" comment="HostName" type="string"
deprecated="true"/>
…
</section>
…
</configvariables>
Normally, the XML output produced by ndb_config --configinfo --xml is formatted using one line per element; we have added extra whitespace in the previous example, as well as the next one, for reasons of legibility. This should not make any difference to applications using this output, since most XML processors either ignore nonessential whitespace as a matter of course, or can be instructed to do so.
The XML output also indicates when changing a given parameter requires that data nodes be restarted using the --initial option. This is shown by the presence of an initial="true" attribute in the corresponding <param> element. In addition, the restart type (system or node) is also shown; if a given parameter requires a system restart, this is indicated by the presence of a restart="system" attribute in the corresponding <param> element. For example, changing the value set for the Diskless parameter requires a system initial restart, as shown here (with the restart and initial attributes highlighted for visibility):
<param name="Diskless" comment="Run wo/ disk" type="bool" default="false"
restart="system" initial="true"/>
Currently, no initial attribute is included in the XML output for <param> elements corresponding to parameters which do not require initial restarts; in other words, initial="false" is the default, and the value false should be assumed if the attribute is not present. Similarly, the default restart type is node (that is, an online or “rolling” restart of the cluster), but the restart attribute is included only if the restart type is system (meaning that all cluster nodes must be shut down at the same time, then restarted).
Deprecated parameters are indicated in the XML output by the deprecated attribute, as shown here:
<param name="NoOfDiskPagesToDiskAfterRestartACC" comment="DiskCheckpointSpeed"
type="unsigned" default="20" min="1" max="4294967039" deprecated="true"/>
In such cases, the comment refers to one or more parameters that supersede the deprecated parameter. Similarly to initial, the deprecated attribute is indicated only when the parameter is deprecated, with deprecated="true", and does not appear at all for parameters which are not deprecated. (Bug #21127135)
Parameters that are required are indicated with mandatory="true", as shown here:
<param name="NodeId"
comment="Number identifying application node (mysqld(API))"
type="unsigned" mandatory="true" min="1" max="255"/>
In much the same way that the initial or deprecated attribute is displayed only for a parameter that requires an intial restart or that is deprecated, the mandatory attribute is included only if the given parameter is actually required.
The --xml option can be used only with the --configinfo option. Using --xml without --configinfo fails with an error.
Unlike the options used with this program to obtain current configuration data, --configinfo and --xml use information obtained from the NDB Cluster sources when ndb_config was compiled. For this reason, no connection to a running NDB Cluster or access to a config.ini or my.cnf file is required for these two options.
| Command-Line Format | --print-defaults |
|---|
Print program argument list and exit.
| Command-Line Format | --defaults-file=path |
|---|---|
| Type | String |
| Default Value | [none] |
Read default options from given file only.
| Command-Line Format | --defaults-extra-file=path |
|---|---|
| Type | String |
| Default Value | [none] |
Read given file after global files are read.
| Command-Line Format | --defaults-group-suffix=string |
|---|---|
| Type | String |
| Default Value | [none] |
Also read groups with concat(group, suffix).
| Command-Line Format | --login-path=path |
|---|---|
| Type | String |
| Default Value | [none] |
Read given path from login file.
| Command-Line Format | --help |
|---|
Display help text and exit.
| Command-Line Format | --connect-string=connection-string |
|---|---|
| Type | String |
| Default Value | [none] |
Same as --ndb-connectstring.
| Command-Line Format | --ndb-mgmd-host=connection-string |
|---|---|
| Type | String |
| Default Value | [none] |
Same as --ndb-connectstring.
| 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 | --core-file |
|---|
Write core file on error; used in debugging.
| Command-Line Format | --character-sets-dir=path |
|---|
Directory containing character sets.
| Command-Line Format | --connect-retries=# |
|---|---|
| Type | Integer |
| Default Value | 12 |
| Minimum Value | 0 |
| Maximum Value | 12 |
Number of times to retry connection before giving up.
| 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.
--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.
Combining other ndb_config options (such as --query or --type) with --configinfo (with or without the --xml option is not supported. Currently, if you attempt to do so, the usual result is that all other options besides --configinfo or --xml are simply ignored. However, this behavior is not guaranteed and is subject to change at any time. In addition, since ndb_config, when used with the --configinfo option, does not access the NDB Cluster or read any files, trying to specify additional options such as --ndb-connectstring or --config-file with --configinfo serves no purpose.
To obtain the node ID and type of each node in the cluster:
shell> ./ndb_config --query=nodeid,type --fields=':' --rows='\n'
1:ndbd
2:ndbd
3:ndbd
4:ndbd
5:ndb_mgmd
6:mysqld
7:mysqld
8:mysqld
9:mysqld
In this example, we used the --fields options to separate the ID and type of each node with a colon character (:), and the --rows options to place the values for each node on a new line in the output.
To produce a connection string that can be used by data, SQL, and API nodes to connect to the management server:
shell> ./ndb_config --config-file=usr/local/mysql/cluster-data/config.ini \
--query=hostname,portnumber --fields=: --rows=, --type=ndb_mgmd
198.51.100.179:1186This invocation of ndb_config checks only data nodes (using the --type option), and shows the values for each node's ID and host name, as well as the values set for its DataMemory and DataDir parameters:
shell> ./ndb_config --type=ndbd --query=nodeid,host,datamemory,datadir -f ' : ' -r '\n'
1 : 198.51.100.193 : 83886080 : /usr/local/mysql/cluster-data
2 : 198.51.100.112 : 83886080 : /usr/local/mysql/cluster-data
3 : 198.51.100.176 : 83886080 : /usr/local/mysql/cluster-data
4 : 198.51.100.119 : 83886080 : /usr/local/mysql/cluster-data
In this example, we used the short options -f and -r for setting the field delimiter and row separator, respectively, as well as the short option -q to pass a list of parameters to be obtained.
To exclude results from any host except one in particular, use the --host option:
shell> ./ndb_config --host=198.51.100.176 -f : -r '\n' -q id,type
3:ndbd
5:ndb_mgmd
In this example, we also used the short form -q to determine the attributes to be queried.
Similarly, you can limit results to a node with a specific ID using the --nodeid option.