MySQL 9.0 Reference Manual Including MySQL NDB Cluster 9.0

25.5.7 ndb_config — Extract NDB Cluster Configuration Information

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.

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.

Examples

  1. To obtain the node ID and type of each node in the cluster:

    $> ./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.

  2. To produce a connection string that can be used by data, SQL, and API nodes to connect to the management server:

    $> ./ndb_config --config-file=usr/local/mysql/cluster-data/config.ini \
    --query=hostname,portnumber --fields=: --rows=, --type=ndb_mgmd
    198.51.100.179:1186
    
  3. This 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:

    $> ./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.

  4. To exclude results from any host except one in particular, use the --host option:

    $> ./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.