MySQL

This component sets up a managed instance of the MySQL database server.

There’s a role for each supported major version, currently:

• mysql57: Percona 5.7.

• mysql80: Percona 8.0.

We use the Percona Distribution for MySQL which provides useful improvements over the standard Oracle MySQL/MariaDB implementations.

Configuration

MySQL works out-of-the box without configuration.

You can change the password for the mysql root user in /etc/local/mysql/mysql.passwd. The MySQL service must be restarted to pick up the new password:

sudo systemctl restart mysql

Custom config files in /etc/local/mysql are included in the main mysql configuration file on the next system build. Add a local.cnf (or any other *.cnf) file there, and run sudo fc-manage --build to activate the new configuration.

Note

Changes to *.cnf files in this directory will restart MySQL to activate the new configuration.

Interaction

You can find the password for the MySQL root user in /etc/local/mysql.passwd. Service users can read the password file.

Service users can use sudo -iu mysql to access the MySQL super user account to perform administrative commands and log files in /var/log/mysql. To connect to the local MySQL server, run mysql as mysql user:

sudo -u mysql mysql

The MySQL server can be accessed from other machines in the same project on the default port 3306.

Slow Log

SQL statements that take longer than 100 milliseconds to run, are logged to /var/log/mysql/mysql.slow. The log file is rotated when file size is greater than 2GB or at least weekly.

The default of 100 milliseconds for slow queries can be changed with a global option: SET GLOBAL long_query_time=1.5; where the value is the time in seconds.

Backup

For backup tasks the xtrabackup command is provided, along with sudo permission for executing xtrabackup from the service user as root.

Monitoring

The default monitoring setup checks that the MySQL server process is running and that it responds to connection attempts to the standard MySQL port.