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.

• --character-sets-dir

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

  Directory containing character sets.

• cluster-config-suffix

  Command-Line Format	--cluster-config-suffix=name
  Type	String
  Default Value	[none]

  Override defaults group suffix when reading cluster configuration sections in my.cnf; used in testing.

• --configinfo

  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:

  $> 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.

• --config-binary-file=path-to-file

  Command-Line Format	--config-binary-file=path/to/file
  Type	File name
  Default Value

  Gives the path to the management server's cached binary configuration file (ndb_nodeID_config.bin.seqno). This may be a relative or absolute path. If the management server and the ndb_config binary used reside on different hosts, you must use an absolute path.

  This example demonstrates combining --config-binary-file with other ndb_config options to obtain useful output:

  $> ndb_config --config-binary-file=../mysql-cluster/ndb_50_config.bin.1 --diff-default --type=ndbd
  config of [DB] node id 5 that is different from default 
  CONFIG_PARAMETER,ACTUAL_VALUE,DEFAULT_VALUE 
  NodeId,5,(mandatory) 
  BackupDataDir,/local/data/8.4,(null) 
  DataDir,/local/data/8.4,. 
  DataMemory,2G,98M 
  FileSystemPath,/local/data/8.4,(null) 
  HostName,127.0.0.1,localhost 
  Nodegroup,0,(null) 
  ThreadConfig,,(null) 
  
  config of [DB] node id 6 that is different from default 
  CONFIG_PARAMETER,ACTUAL_VALUE,DEFAULT_VALUE 
  NodeId,6,(mandatory) 
  BackupDataDir,/local/data/8.4,(null) 
  DataDir,/local/data/8.4. 
  DataMemory,2G,98M 
  FileSystemPath,/local/data/8.4,(null) 
  HostName,127.0.0.1,localhost 
  Nodegroup,0,(null) 
  ThreadConfig,,(null)
  
  $> ndb_config --config-binary-file=../mysql-cluster/ndb_50_config.bin.1 --diff-default --system
  config of [SYSTEM] system 
  CONFIG_PARAMETER,ACTUAL_VALUE,DEFAULT_VALUE 
  Name,MC_20220906060042,(mandatory) 
  ConfigGenerationNumber,1,0 
  PrimaryMGMNode,50,0

  The relevant portions of the config.ini file are shown here:

  [ndbd default]
  DataMemory= 2G
  NoOfReplicas= 2
  
  [ndb_mgmd]
  NodeId= 50
  HostName= 127.0.0.1
  
  [ndbd]
  NodeId= 5
  HostName= 127.0.0.1
  DataDir= /local/data/8.4
  
  [ndbd]
  NodeId= 6
  HostName= 127.0.0.1
  DataDir= /local/data/8.4

  By comparing the output with the configuration file, you can see that all of the settings in the file have been written by the management server to the binary cache, and thus, applied to the cluster.

• --config-file=path-to-file

  Command-Line Format	--config-file=file_name
  Type	File name
  Default Value

  Gives the path to the cluster configuration file (config.ini). This may be a relative or absolute path. If the management server and the ndb_config binary used reside on different hosts, you must use an absolute path.

• --config_from_node=#

  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.)

• --connect-retries

  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.

• --connect-retry-delay

  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

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

  Same as --ndb-connectstring.

• --connections

  Command-Line Format	--connections

  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 25.4.3.10, “NDB Cluster TCP/IP Connections”, and Section 25.4.3.12, “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.

• --core-file

  Command-Line Format	--core-file

  Write core file on error; used in debugging.

• --defaults-extra-file

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

  Read given file after global files are read.

• --defaults-file

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

  Read default options from given file only.

• --defaults-group-suffix

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

  Also read groups with concat(group, suffix).

• --diff-default

  Command-Line Format	--diff-default

  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).

  Note

  If the delimiter contains spaces or escapes (such as \n for the linefeed character), then it must be quoted.

• --help

  Command-Line Format	--help

  Display help text and exit.

• --host=hostname

  Command-Line Format	--host=name
  Type	String
  Default Value

  Specifies the host name of the node for which configuration information is to be obtained.

  Note

  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.

• --login-path

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

  Read given path from login file.

• --mycnf

  Command-Line Format	--mycnf

  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 25.4.3.3, “NDB Cluster Connection Strings”, and defaults to localhost:1186.

• --ndb-mgm-tls

  Command-Line Format	--ndb-mgm-tls=level
  Type	Enumeration
  Default Value	relaxed
  Valid Values	relaxed strict

  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.

• --ndb-mgmd-host

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

  Same as --ndb-connectstring.

• --ndb-nodeid

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

  Set node ID for this node, overriding any ID set by --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.

• --ndb-tls-search-path

  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.

• --no-defaults

  Command-Line Format	--no-defaults

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

• --no-login-paths

  Command-Line Format	--no-login-paths

  Skips reading options from the login path file.

• --nodeid=node_id

  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.

• --nodes

  Command-Line Format	--nodes

  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 25.4.3.6, “Defining NDB Cluster Data Nodes”).

  This option is mutually exclusive with --connections and --system; only one of these 3 options can be used.

• --print-defaults

  Command-Line Format	--print-defaults

  Print program argument list and exit.

• --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.

  Note

  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.

• --query-all, -a

  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.

  Note

  If the separator contains spaces or escapes (such as \n for the linefeed character), then it must be quoted.

• --system

  Command-Line Format	--system

  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.

• --type=node_type

  Command-Line Format	--type=name
  Type	Enumeration
  Default Value	[none]
  Valid Values	ndbd mysqld ndb_mgmd

  Filters results so that only configuration values applying to nodes of the specified node_type (ndbd, mysqld, or ndb_mgmd) are returned.

• --usage, --help, or -?

  Command-Line Format	--help

  Causes ndb_config to print a list of available options, and then exit.

• --version, -V

  Command-Line Format	--version

  Causes ndb_config to print a version information string, and then exit.

• --configinfo --xml

  Command-Line Format	--configinfo --xml

  Cause ndb_config --configinfo to provide output as XML by adding this option. A portion of such output is shown in this example:

  $> ndb_config --configinfo --xml
  
  <configvariables protocolversion="1" ndbversionstring="5.7.44-ndb-7.5.36"
                      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>

  Note

  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 initial restart or that is deprecated, the mandatory attribute is included only if the given parameter is actually required.

  Important

  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.

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.