MySQL™ Cluster Manager 1.4.8 User Manual
mcmd is the MySQL Cluster Manager agent program; invoking this executable starts the MySQL Cluster Manager Agent, to which you can connect using the mcm client (see Section 3.3, “Starting the MySQL Cluster Manager Client”, and Chapter 4, MySQL Cluster Manager Client Commands, for more information).
You can modify the behavior of the agent in a number of different
ways by specifying one or more of the options discussed in this
sections. Most of these options can be specified either on the
command line or in the agent configuration file (normally
etc/mcmd.ini). (Some exceptions include the
--defaults-file and
--bootstrap options, which, if used,
must be specified on the command line, and which are mutually
exclusive with one another.) For example, you can set the
agent's cluster logging level to warning
instead than the default message in either one of
the following two ways:
Include --log-level=warning on the
command line when invoking mcmd.
When specifying an agent configuration option on the command
line, the name of the option is prefixed with two leading dash
characters (--).
Include the following line in the agent configuration file:
log-level=warning
You can change the logging level at runtime using the
mcm client change
log-level command.
When used in the configuration file, the name of the option
should not be prefixed with any other characters. Each option
must be specified on a separate line. You can comment out all of
a given line by inserting a leading hash character
(#), like this:
#log-level=warning
You can also comment out part of a line in this way; any text
following the # character is ignored, to the
end of the current line.
The following table contains a summary of agent options that are read on startup by mcmd. More detailed information about each of these options, such as allowed range of values, can be found in the list following the table.
Table 3.1 MySQL Cluster Manager Agent (mcmd) Option Summary
| Option Name | Description | Introduced |
|---|---|---|
| --agent-uuid | Set the agent's UUID; needed only when running multiple agent processes on the same host | |
| --basedir | Directory to use as prefix for relative paths in the configuration | |
| --bootstrap | Bootstrap a default cluster on startup | |
| --copy-port | Specify the port for file copy operations | 1.4.2 |
| --daemon | Run in daemon mode. The option applies only to Linux and other Unix-like platforms | |
| --defaults-file | Configuration file to use | |
| --event-threads | Number of event handler threads to use | |
| --help | Show application options | |
| --help-all | Show all options (application options and manager module options) | |
| --help-manager | Show manager module options | |
| --initial | Wipes the contents in the agent's configuration store after making a backup | 1.4.7 |
| --keepalive | Try to restart mcmd in the event of a crash. The option applies only to Linux and other Unix-like platforms | |
| --log-backtrace-on-crash | Attempt to load debugger in case of a crash | |
| --log-file | Name of the file to write the log to | |
| --log-level | Set the mcmd logging level | |
| --log-use-syslog | Log to syslog | |
| --manager-directory | Directory used for manager data storage | |
| --manager-password | Password for the mcmd user-account | |
| --manager-port | Port for client to use when connecting to manager | |
| --manager-username | Username for the mcmd user-account | |
| --max-open-files | Maximum number of open files (ulimit -n) | |
| --pid-file | Specify PID file (used if running as daemon) | |
| --plugin-dir | Directory in which to look for plugins | |
| --plugins | Comma-separated list of plugins to load; must include "manager" | |
| --verbose-shutdown | Always log the exit code when shutting down | |
| --version | Show the manager version | |
| --xcom-port | Specify the XCOM port |
mcmd) Option DescriptionsThe following list contains descriptions of each startup option available for use with mcmd, including allowed and default values. Options with their Type unmentioned need only be specified in order to take effect; you should not try to set a value for them.
| Command-Line Format | --agent-uuid=uuid |
|---|---|
| Type | String |
| Default Value | [set internally] |
Set a UUID for this agent. Normally this value is set automatically, and needs to be specified only when running more than one mcmd process on the same host.
| Command-Line Format | --basedir=dir_name |
|---|---|
| Type | Directory name |
| Default Value | . |
Directory with path to use as prefix for relative paths in the configuration.
| Command-Line Format | --bootstrap |
|---|
Start the agent with default configuration values, create a
default one-machine cluster named mycluster,
and start it. This option works only if no clusters have yet
been created.
| Command-Line Format | --copy-port=port |
|---|---|
| Introduced | 1.4.2 |
| Type | Numeric |
| Default Value | 0 |
Allows you to specify the port for file copy operations. The default is 0.
| Command-Line Format | --daemon |
|---|---|
| Platform Specific | Linux |
Run mcmd as a daemon.
| Command-Line Format | --defaults-file=file_name |
|---|---|
| Type | File name |
| Default Value | etc/mcmd.ini |
Set the file from which to read configuration options. The
default is etc/mcmd.ini. See
Section 2.4, “MySQL Cluster Manager Configuration File”, for more
information.
| Command-Line Format | --event-threads=# |
|---|---|
| Type | Numeric |
| Default Value | 1 |
| Minimum Value | 1 |
| Maximum Value | [system dependent] |
Number of event handler threads to use. The the default is 1, which is sufficient for most normal operations.
--help, -?
| Command-Line Format | --help |
|---|
mcmd help output is divided into
Application and
Manager sections. When used with
mcmd, --help causes the
Application options to be shown, as shown
here:
shell> mcmd --help
Usage:
mcmd [OPTION...] - MySQL Cluster Manager
Help Options:
-?, --help Show help options
--help-all Show all help options
--help-manager Show options for the manager-module
Application Options:
-V, --version Show version
--defaults-file=<file> configuration file
--verbose-shutdown Always log the exit code when shutting down
--daemon Start in daemon-mode
--basedir=<absolute path> Base directory to prepend to relative paths in the config
--pid-file=<file> PID file in case we are started as daemon
--plugin-dir=<path> Path to the plugins
--plugins=<name> Plugins to load
--log-level=<string> Log all messages of level ... or higher
--log-file=<file> Log all messages in a file
--log-use-syslog Log all messages to syslog
--log-backtrace-on-crash Try to invoke debugger on crash
--keepalive Try to restart mcmd if it crashed
--max-open-files Maximum number of open files (ulimit -n)
--event-threads Number of event-handling threads (default: 1)
| Command-Line Format | --help-all |
|---|
mcmd help output is divided into
Application and
Manager sections. When used with
--help-all, mcmd displays
both the Application and the
Manager options, like this:
shell> mcmd --help-all
Usage:
mcmd [OPTION...] - MySQL Cluster Manager
Help Options:
-h, --help Show help options
--help-all Show all help options
--help-manager Show options for the manager-module
manager-module
--bootstrap Bootstrap a cluster on localhost on initial startup
--copy-port=<copy_port> Port for file copy operations (default: 0)
--initial Wipes the repository files after making a backup
--manager-directory=<directory> Path to mcmd config information
--manager-password=<password> Password for the mcmd user-account (default: super)
--manager-port=<client_port> Port to contact the mcmd (default: 1862)
--manager-username=<username> Username for the mcmd user-account (default: mcmd)
--xcom-port=<xcom_port> Xcom port for mcmds to communicate (default: 18620)
Application Options:
-V, --version Show version
--defaults-file=<file> configuration file
--verbose-shutdown Always log the exit code when shutting down
--daemon Start in daemon-mode
--basedir=<absolute path> Base directory to prepend to relative paths in the config
--pid-file=<file> PID file in case we are started as daemon
--plugin-dir=<path> Path to the plugins
--plugins=<name> Plugins to load
--log-level=<string> Log all messages of level ... or higher
--log-file=<file> Log all messages in a file
--log-use-syslog Log all messages to syslog
--log-backtrace-on-crash Try to invoke debugger on crash
--keepalive Try to restart mcmd if it crashed
--max-open-files Maximum number of open files (ulimit -n)
--event-threads Number of event-handling threads (default: 1)
| Command-Line Format | --help-manager |
|---|
mcmd help output is divided into
Application and
Manager sections. When used with
--help-manager, mcmd
displays the Manager options, like this:
shell> mcmd --help-manager
Usage:
mcmd [OPTION...] - MySQL Cluster Manager
manager-module
--bootstrap Bootstrap a cluster on localhost on initial startup
--copy-port=<copy_port> Port for file copy operations (default: 0)
--initial Wipes the repository files after making a backup
--manager-directory=<directory> Path to mcmd config information
--manager-password=<password> Password for the mcmd user-account (default: super)
--manager-port=<client_port> Port to contact the mcmd (default: 1862)
--manager-username=<username> Username for the mcmd user-account (default: mcmd)
--xcom-port=<xcom_port> Xcom port for mcmds to communicate (default: 18620)
| Command-Line Format | --initial |
|---|---|
| Introduced | 1.4.7 |
For MySQL Cluster Manager 1.4.7 and later: Make a backup of
the agent's configuration store
(mcm_data/rep/) like the
backup agents command would do
for the local host, and then wipe the configuration store's
contents before starting mcmd. The agent's
configuration is then recovered from other agents. This is
useful when an agent has fallen into an inconsistent state and
cannot be properly restarted.
| Command-Line Format | --keepalive |
|---|---|
| Platform Specific | Linux |
Use this option to cause mcmd to attempt to restart in the event of a crash.
| Command-Line Format | --log-backtrace-on-crash |
|---|
Attempt to load the debugger in the event of a crash. Not normally used in production.
| Command-Line Format | --log-file=file |
|---|---|
| Type | File name |
| Default Value | mcmd.log |
Set the name of the file to write the log to. The default is
mcmd.log in the installation directory. On
Linux and other Unix-like platforms, you can use a relative
path; this is in relation to the MySQL Cluster Manager installation directory,
and not to the bin or
etc subdirectory. On Windows, you must use
an absolute path, and it cannot contain any spaces; in addition,
you must replace any backslash (\) characters
in the path with forward slashes (/).
| Command-Line Format | --log-level=level |
|---|---|
| Type | Enumeration |
| Default Value | message |
| Valid Values |
|
Sets the mcmd log severity level. Possible
values for this option and their descriptions are listed in
Table 3.2, “MySQL Cluster Manager Agent Log Levels” in descending level of
severity. When the option is set to a certain severity level,
all events of that or higher levels are logged.
message is the default log level, and is the
recommended setting for a production environment; running on a
more severe log level produces fewer messages and makes it
harder to trace a problem when it occurs.
Table 3.2 MySQL Cluster Manager Agent Log Levels
| Level of Severity | Description |
|---|---|
critical |
Conditions that should be corrected immediately, such as a corrupted MySQL Cluster Manager data repository |
error |
Conditions that should be corrected, such as configuration errors |
warning |
Conditions that do not fail executions, but may require user attention |
message |
Messages on main events of the site and from command execution |
info |
Informational messages to provide users with some execution details |
debug |
Debugging messages that give execution details useful for developers. This causes large log files if used over a long period of time. |
You can also change the mcmd logging level at
runtime using the change
log-level command with the mcm
client. While the setting of the
--log-level option is applied only
to the host whose mcmd agent uses the option
(either at the command line or in a configuration file), the
change log-level client command
can be used to apply the logging level to an entire management
site or to specific hosts.
| Command-Line Format | --log-use-syslog |
|---|
Write logging output to syslog.
| Command-Line Format | --manager-directory=dir |
|---|---|
| Type | Directory name |
| Default Value | ../mcm_data (relative to the installation directory of MySQL Cluster Manager) |
Set the location of the agent repository, which contains
collections of MySQL Cluster Manager data files and MySQL NDB Cluster configuration and
data files. The value must be a valid absolute path. On Linux,
if the directory does not exist, it is created; on Windows, the
directory must be created if it does not exist. additionally on
Windows, the path may not contain any spaces or backslash
(\) characters; backslashes must be replaced
with forward slashes (/).
The default location is ../mcm_data
(relative to the installation directory of MySQL Cluster Manager). If you change
the default, you should use a standard location external to the
MySQL Cluster Manager installation directory, such as
/var/opt/mcm on Linux.
In addition to the data files for all the clusters under the
control of MySQL Cluster Manager, the manager-directory also contains a
rep directory in which
mcmd configuration and metadata are kept.
Normally, there is no need to interact with these directories
beyond specifying the location of the
manager-directory in the agent configuration
file (mcmd.ini); see exceptions in, for
example, Section 3.8, “Restoring a MySQL Cluster Manager Agent with Data from Other Agents” and
Section 3.7, “Backing Up and Restoring MySQL Cluster Manager Agents”.
| Command-Line Format | --manager-port=port |
|---|---|
| Type | Numeric |
| Default Value | localhost:1862 |
Specify the port used by MySQL Cluster Manager client connections. Any valid TC/IP port number can be used. Normally, there is no need to change it from the default value (1862).
Previously, this option could optionally take a host name in addition to the port number, but in MySQL Cluster Manager 1.1.1 and later the host name is no longer accepted.
The option serves the following two purposes:
Sets the user name for an mcm client to
connect to the mcmd agent. If the option
is not specified, the default value of
mcmd is used. If the option is specified
with another value, the client must supply it using the
--user client option when trying
to connect to the agent.
The password for using this user name to connect to the
agent is set with the
--manager-password option.
Sets a user name for the MySQL account to be used by the
mcmd agent to access the SQL nodes. If
the option is not specified, the default value of
mcmd is used.
When an SQL node is initialized, the mcmd
agent creates a new MySQL user account on it using the user
name set by the option and the password set by the
--manager-password option.
This account is created with all privileges on the
MySQL server including the granting of
privileges. In other words, it is created as if
you had executed
GRANT ALL PRIVILEGES
ON *.* ... WITH GRANT OPTION in the
mysql client. The existing MySQL
root account is not altered in such
cases, and the default test database is
preserved.
The option serves the following two purposes:
Sets the user password for an mcm client
to connect to the mcmd agent with the
user name set by
--manager-username. If the
option is not specified, the default value of
super is used. If the option is specified
with another value, the client must supply it using the
--password client option when
trying to connect to the agent.
Sets a password for the MySQL account to be used by the
mcmd agent to access the SQL nodes. If
the option is not specified, the default value of
super is used.
When an SQL node is initialized, the mcmd
agent creates a new MySQL user account on it using the user
name set by the
--manager-username option and
the password set by this option. See descriptions of
--manager-username for more
details about the account.
| Command-Line Format | --max-open-files=# |
|---|---|
| Type | Numeric |
| Default Value | 1 |
| Minimum Value | 1 |
| Maximum Value | [system dependent] |
Set the maximum number of open files (as with ulimit -n).
| Command-Line Format | --pid-file=file_name |
|---|---|
| Type | File name |
| Default Value | mcmd.pid |
Set the name and path to a process ID
(.pid) file. Not normally used or needed.
This option is not supported on Windows systems.
| Command-Line Format | --plugin-dir=dir_name |
|---|---|
| Type | Directory name |
| Default Value | lib/mcmd |
Set the directory to search for plugins. The default is
lib/mcmd, in the MySQL Cluster Manager installation
directory; normally there is no need to change this.
| Command-Line Format | --plugins=list |
|---|---|
| Type | Directory name |
| Default Value | manager |
Specify a list of plugins to be loaded on startup. To enable
MySQL Cluster Manager, this list must include manager (the
default value). Please be aware that we currently do not test
MySQL Cluster Manager with any values for plugins other than
manager. Therefore, we recommend using the
default value in a production setting.
| Command-Line Format | --verbose-shutdown |
|---|
Force mcmd to log the exit code whenever
shutting down, regardless of the reason.
--version, -V
| Command-Line Format | --version |
|---|
Display version information and exit. Output may vary according to the MySQL Cluster Manager software version, operating platform, and versions of libraries used on your system, but should closely resemble what is shown here, with the first line of output containing the MySQL Cluster Manager release number (emphasized text):
shell> mcmd --version
MySQL Cluster Manager 1.4.8 (64bit)
chassis: 0.8.5.15734304
glib2: 2.44.0
libevent: 2.1.11-stable
-- modules
manager: 1.4.8
| Command-Line Format | --xcom-port=port |
|---|---|
| Type | Numeric |
| Default Value | 18620 |
Allows you to specify the XCOM port. The default in 18620.