MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
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.
The following table includes options that are specific to ndb_config. Additional descriptions follow the table. For options common to most NDB Cluster programs (including ndb_config), see Section 20.4.32, “Options Common to NDB Cluster Programs — Options Common to NDB Cluster Programs”.
Table 20.27 Command-line options for the ndb_config program
| Format | Description | Added, Deprecated, or Removed |
|---|---|---|
| Set the path to config.ini file | (Supported in all MySQL 5.7 based releases) |
|
| Obtain configuration data from the node having this ID (must be a data node) | (Supported in all MySQL 5.7 based releases) |
|
| 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 MySQL 5.7 based releases) |
|
| 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 MySQL 5.7 based releases) |
|
| Print only configuration parameters that have non-default values | ADDED: NDB 7.5.7, NDB 7.6.3 |
|
| Field separator | (Supported in all MySQL 5.7 based releases) |
|
| Specify host | (Supported in all MySQL 5.7 based releases) |
|
| Read configuration data from my.cnf file | (Supported in all MySQL 5.7 based releases) |
|
| Get configuration of node with this ID | (Supported in all MySQL 5.7 based releases) |
|
| Print node information ([ndbd] or [ndbd default] section of cluster configuration file) only. Cannot be used with --system or --connections | (Supported in all MySQL 5.7 based releases) |
|
| Short form for --ndb-connectstring | (Supported in all MySQL 5.7 based releases) |
|
| One or more query options (attributes) | (Supported in all MySQL 5.7 based releases) |
|
| Dumps all parameters and values to a single comma-delimited string | ADDED: NDB 7.4.16, NDB 7.5.7 |
|
| Row separator | (Supported in all MySQL 5.7 based releases) |
|
| Print SYSTEM section information only (see ndb_config --configinfo output). Cannot be used with --nodes or --connections | (Supported in all MySQL 5.7 based releases) |
|
| Specify node type | (Supported in all MySQL 5.7 based releases) |
|
| 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 MySQL 5.7 based releases) |
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 20.3.3.10, “NDB Cluster TCP/IP Connections”,
and Section 20.3.3.12, “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 |
|---|---|
| Introduced | 5.7.18-ndb-7.6.3 |
| 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 |
|
|---|---|
| Type | String |
| Default Value | localhost:1186 |
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 20.3.3.3, “NDB Cluster Connection Strings”, and
defaults to localhost:1186.
| Command-Line Format | --ndb-nodeid=# |
|---|---|
| Type | Numeric |
| Default Value | 0 |
Specify the node ID of the node for which configuration
information is to be obtained. Formerly,
--id could be used as a synonym for this
option; in NDB 7.5 and later, the only form accepted is
--nodeid.
| 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 20.3.3.6, “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.
Formerly, id was accepted as a synonym
for nodeid, but has been removed in NDB
7.5 and later.
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 |
|---|---|
| Introduced | 5.7.18-ndb-7.5.7 |
| Type | String |
| Default Value | |
Returns a comma-delimited list of all query options (node attributes; note that this list is a single string.
This option was introduced in NDB 7.5.7 (Bug #60095, Bug #11766869).
--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 |
|
|---|
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-7.5.22"
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)
Beginning with NDB 7.5.0, 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.
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
198.51.100.179:1186
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:
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.