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.NoteWhen 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
NoteYou 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 |
---|---|
--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 |
--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 |
--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 |
MySQL Cluster Manager Agent (mcmd
) Option Descriptions
The following list contains descriptions of each startup option available for use with mcmd, including allowed and default values. Options noted as boolean need only be specified in order to take effect; you should not try to set a value for these.
-
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. This option is mutually exclusive with the--defaults-file
option.Currently, any data stored in the default cluster
mycluster
is not preserved between cluster restarts. -
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 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:$> 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:> mcmd --help-all 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 manager-module --manager-port=<clientport> Port to manage the cluster (default: 1862) --xcom-port=<xcomport> Xcom port (default: 18620) --manager-username=<username> Username to manage the cluster (default: mcmd) --manager-password=<password> Password for the manager user-account (default: super) --bootstrap Bootstrap a default cluster on initial startup --manager-directory=<directory> Path to managers config information 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:$> mcmd --help-manager Usage: mcmd [OPTION...] - MySQL Cluster Manager manager-module --manager-port=<clientport> Port to manage the cluster (default: 1862) --xcom-port=<xcomport> Xcom port (default: 18620) --manager-username=<username> Username to manage the cluster (default: mcmd) --manager-password=<password> Password for the manager user-account (default: super) --bootstrap Bootstrap a default cluster on initial startup --manager-directory=<directory> Path to managers config information
-
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 thebin
oretc
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 critical
error
warning
message
info
debug
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 thechange 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), thechange 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 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 MySQL Cluster Manager data files, the
manager-directory
also contains arep
directory in which MySQL Cluster data files for each MySQL Cluster under MySQL Cluster Manager control are kept. Normally, there is no need to interact with these directories beyond specifying the location of themanager-directory
in the agent configuration file (mcmd.ini
).However, in the event that an agent reaches an inconsistent state, it is possible to delete the contents of the
rep
directory, in which case the agent attempts to recover its repository from another agent. In such cases, you must also delete therepchksum
file and thehigh_water_mark
file from themanager-directory
. Otherwise, the agent reads these files and raises errors due to the now-emptyrep
directory. -
Command-Line Format --manager-password=password
Type String Default Value super
Set a password to be used for the manager agent user account. The default is
super
.Using this option together with
manager-username
causes the creation of a MySQL user account, having the username and password specified using these two options. 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 executedGRANT ALL PRIVILEGES ON *.* ... WITH GRANT OPTION
in the mysql client. -
Command-Line Format --manager-port=port
Type Numeric Default Value 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.
-
Command-Line Format --manager-username=name
Type String Default Value mcmd
Set a user name for the MySQL account to be used by the MySQL Cluster Manager agent. The default is
mcmd
.When used together with
manager-password
, this option also causes the creation of a new MySQL user account, having the user name and password specified using these two options. 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 executedGRANT ALL PRIVILEGES ON *.* ... WITH GRANT OPTION
in the mysql client. The existing MySQLroot
account is not altered in such cases, and the defaulttest
database is preserved. -
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 forplugins
other thanmanager
. 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):
$> mcmd -V MySQL Cluster Manager 1.3.6 (64bit) chassis: mysql-proxy 0.8.3 glib2: 2.16.6 libevent: 1.4.13-stable -- modules manager: 1.3.6
-
Command-Line Format --xcom-port=#
Type Numeric Default Value 18620
Minimum Value 1
Maximum Value 65535
Allows you to specify the XCOM port. The default in 18620.