This article was last reviewed for Debian 8 (Jessie).
MySQL 5.5 installation and configuration (Debian, repository)
| Author: | Stefán Örvar Sigmundsson |
|---|---|
| Initial publication: | |
| Last updated: | |
| Written in: | English (United Kingdom) |
MySQL is the world's most popular open-source relational database management system (RDBMS). This article will demonstrate how to install and configure MySQL 5.5 on Debian or its derivatives such as Ubuntu and Linux Mint.
Installation
MySQL can be installed from the official Debian repository using APT:
root@computer:~# apt --assume-yes install mysql-server-5.5
The user is prompted during the installation for a password for the newly created root MySQL user.
Configuration
The default log files for MySQL are deleted as a new one (error.log) will be created in a dedicated directory (/var/log/mysql) for organisational purposes:
root@computer:~# rm /var/log/mysql.err root@computer:~# rm /var/log/mysql.log
A file is created to contain the error log for MySQL in a dedicated directory:
root@computer:~# touch /var/log/mysql/error.log
A directory is created to contain the temporary files created by MySQL for various purposes:
root@computer:~# mkdir /var/tmp/mysql/
There is a lot of clutter in the default configuration file even though it is operational. Clearing it will ensure that there is no conflict nor confusion:
root@computer:~# > /etc/mysql/my.cnf
my.cnf
The my.cnf file contains MySQL's primary configuration:
[client]
port = 3306
[mysqld]
basedir = /usr
bind-address = 127.0.0.1
character-set-server = utf8mb4
collation-server = utf8mb4_unicode_ci
datadir = /var/lib/mysql/
log-error = /var/log/mysql/error.log
pid-file = /run/mysqld/mysqld.pid
port = 3306
socket = /run/mysqld/mysqld.sock
tmpdir = /var/tmp/mysql/
user = mysql[client]- Sets the configuration scope for the subsequent directives to client. The client scope includes all of the client programs that come in the installed software packages so that they need no be configured individually.
port = 3306- The port to which to connect.
[mysqld]- Sets the configuration scope for the subsequent directives to mysqld. The name of the MySQL service is mysqld by default on Debian.
basedir = /usr- The base directory is /usr by default on Debian.
bind-address = 127.0.0.1- The IP address to which to listen for connections.
character-set-server = utf8mb4- The default character set for the server.
collation-server = utf8mb4_unicode_ci- The default collation for the server.
datadir = /var/lib/mysql/- The data directory of MySQL is /var/lib/mysql/ by default on Debian.
log-error = /var/log/mysql/error.log- The log file of MySQL is /var/log/mysql/error.log by default on Debian.
pid-file = /var/run/mysqld/mysqld.pid- The PID file of MySQL.
port = 3306- The port to which to listen on for connections.
socket = /run/mysqld/mysqld.sock- The socket file of MySQL.
tmpdir = /var/tmp/mysql/- A directory (/var/tmp/mysql/) is created to contain temporary files.
user = mysql- The OS user of MySQL is mysql by default on Debian.
Conclusion
Log rotation
The package installs a default logrotate configuration file (/etc/logrotate.d/mysql-server) that can be customised:
/var/log/mysql/*.log
{
copytruncate
maxage 365
missingok
monthly
notifempty
rotate 12
}/var/log/mysql/*.log- Sets the configuration scope for the subsequent section. The pattern matches all files (*) ending with the extension log in the /var/log/mysql/ directory.
copytruncate- Copy the contents of the log file being rotated into a new file and then truncate the original log file.
maxage 365- Remove log files older than 365 days.
missingok- Do not consider it an error if a log file is missing.
monthly- Perform a log rotation monthly.
notifempty- Do not perform a log rotation on an empty log file.
rotate 12- Perform 12 log rotations before older log files are removed.
Directory ownership and permissions
The configuration directory should be protected:
root@computer:~# chown --recursive root:adm /etc/mysql/ root@computer:~# chmod --recursive 0770 /etc/mysql/
The log directory should be protected:
root@computer:~# chown --recursive mysql:adm /var/log/mysql/ root@computer:~# chmod --recursive 0750 /var/log/mysql/
The temporary file directory should be protected:
root@computer:~# chown --recursive mysql:mysql /var/tmp/mysql/ root@computer:~# chmod --recursive 0770 /var/tmp/mysql/
Server reinitiation
MySQL is restarted when the configuration is done:
root@computer:~# systemctl restart mysql.service