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4.6.10.3. Starting the MySQL Server with MySQL Instance Manager

Important

MySQL Instance Manager has been deprecated and is removed in MySQL 5.4.

This section discusses how Instance Manager starts server instances when it starts. However, before you start Instance Manager, you should set up a password file for it. Otherwise, you will not be able to connect to Instance Manager to control it after it starts. For details about creating Instance Manager accounts, see Section 4.6.10.4, “Instance Manager User and Password Management”.

On Unix, the mysqld MySQL database server normally is started with the mysql.server script, which usually resides in the /etc/init.d/ folder. That script invokes the mysqld_safe script by default. However, you can use Instance Manager instead if you modify the /etc/my.cnf configuration file by adding use-manager to the [mysql.server] section: 

[mysql.server]
use-manager

Before MySQL 5.1.12, Instance Manager always tries to start at least one server instance: When it starts, it reads its configuration file if it exists to find server instance sections and prepare a list of instances. Instance sections have names of the form [mysqld] or [mysqldN], where N is an unsigned integer (for example, [mysqld1], [mysqld2], and so forth).

After preparing the list of instances, Instance Manager starts the guarded instances in the list. If there are no instances, Instance Manager creates an instance named mysqld and attempts to start it with default (compiled-in) configuration values. This means that the Instance Manager cannot find the mysqld program if it is not installed in the default location. (Section 2.1.5, “Installation Layouts”, describes default locations for components of MySQL distributions.) If you have installed the MySQL server in a nonstandard location, you should create the Instance Manager configuration file.

The startup behavior just described is similar to that of mysqld_safe, which always attempts to start a server. However, it lacks the flexibility required for some operations because it is not possible to run Instance Manager in such a way that it refrains from starting any server instances. For example, you cannot invoke Instance Manager for the purpose of configuring an instance without also starting it (a task that a MySQL installer application might want to perform). Consequently, MySQL 5.1.12 introduces the following changes:

  • A new option, --mysqld-safe-compatible, may be used to cause Instance Manager to run with startup behavior similar to that used before MySQL 5.1.12: If Instance Manager finds a [mysqld] instance section in the configuration file, it will start it. If Instance Manager finds no [mysqld] section, it creates one using default configuration values, writes a [mysqld] section to the configuration file if it is accessible, and starts the mysqld instance. Instance Manager also starts any other guarded instances listed in the configuration file.

  • Without --mysqld-safe-compatible, Instance Manager reads its configuration file if it exists and starts instances for any guarded instance sections that it finds. If there are none, it starts no instances.

Instance Manager also stops all guarded server instances when it shuts down.

The allowable options for [mysqldN] server instance sections are described in Section 4.6.10.2, “MySQL Instance Manager Configuration Files”. In these sections, you can use a special mysqld-path=path-to-mysqld-binary option that is recognized only by Instance Manager. Use this option to let Instance Manager know where the mysqld binary resides. If there are multiple instances, it may also be necessary to set other options such as datadir and port, to ensure that each instance has a different data directory and TCP/IP port number. Section 5.6, “Running Multiple MySQL Servers on the Same Machine”, discusses the configuration values that must differ for each instance when you run multiple instance on the same machine.

Warning

The [mysqld] instance section, if it exists, must not contain any Instance Manager-specific options.

The typical Unix startup/shutdown cycle for a MySQL server with the MySQL Instance Manager enabled is as follows:

  1. The /etc/init.d/mysql script starts MySQL Instance Manager.

  2. Instance Manager starts the guarded server instances and monitors them.

  3. If a server instance fails, Instance Manager restarts it.

  4. If Instance Manager is shut down (for example, with the /etc/init.d/mysql stop command), it shuts down all server instances.