MediaWiki-Docker/Configuration recipes/Alternative databases

Alternative databases

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The default configuration uses SQLite for the database backend, but you can use MySQL (with replication or without) or Postgres instead.

MariaDB (single database server)

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These instruction assume a new installation (no LocalSettings.php).

docker-compose.override.yml
services:
  mariadb:
    image: 'bitnami/mariadb:latest'
    volumes:
      - mariadbdata:/bitnami/mariadb
    environment:
      - MARIADB_ROOT_PASSWORD=root_password
      - MARIADB_USER=my_user
      - MARIADB_PASSWORD=my_password
      - MARIADB_DATABASE=my_database
    ports:
      - 3306:3306
volumes:
  mariadbdata:
    driver: local

To install MediaWiki, open a bash shell in the container:

docker compose exec mediawiki /bin/bash

In this bash shell, install MediaWiki with the following command:

php maintenance/run.php install --dbname=my_database --dbuser=my_user --dbpass=my_password --dbserver=mariadb --server="${MW_SERVER}" --scriptpath="${MW_SCRIPT_PATH}" --lang en --pass ${MEDIAWIKI_PASSWORD} mediawiki ${MEDIAWIKI_USER}

MariaDB (database replication)

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This is the configuration recipe that is most like Wikimedia production.

These instruction assume a new installation (no LocalSettings.php).

docker-compose.override.yml
services:
  mariadb-main:
    image: 'bitnami/mariadb:latest'
    volumes:
      - mariadbdata:/bitnami/mariadb
    environment:
      - MARIADB_REPLICATION_MODE=master
      - MARIADB_REPLICATION_USER=repl_user
      - MARIADB_REPLICATION_PASSWORD=repl_password
      - MARIADB_ROOT_PASSWORD=main_root_password
      - MARIADB_USER=my_user
      - MARIADB_PASSWORD=my_password
      - MARIADB_DATABASE=my_database
  mariadb-replica:
    image: 'bitnami/mariadb:latest'
    depends_on:
      - mariadb-main
    environment:
      - MARIADB_REPLICATION_MODE=slave
      - MARIADB_REPLICATION_USER=repl_user
      - MARIADB_REPLICATION_PASSWORD=repl_password
      - MARIADB_MASTER_HOST=mariadb-main
      - MARIADB_MASTER_PORT_NUMBER=3306
      - MARIADB_MASTER_ROOT_PASSWORD=main_root_password
volumes:
  mariadbdata:
    driver: local

To install MediaWiki, open a bash shell in the container:

docker compose exec mediawiki /bin/bash

In this bash shell, install MediaWiki with the following command:

php maintenance/install.php --dbname=my_database --dbuser=my_user --dbpass=my_password --dbserver=mariadb-main \
--server="${MW_SERVER}" --scriptpath="${MW_SCRIPT_PATH}" --lang en \
--pass ${MEDIAWIKI_PASSWORD} mediawiki ${MEDIAWIKI_USER}

After installing, add these snippets so that MediaWiki knows to read from the replica but write to the main database.

LocalSettings.php
$wgDBname = 'my_database';
$dockerMainDb = [
	'host' => "mariadb-main",
	'dbname' => 'my_database',
	'user' => 'root',
	'password' => 'main_root_password',
	'type' => "mysql",
	'flags' => DBO_DEFAULT,
	'load' => 0,
];
$dockerReplicaDb = [
	'host' => "mariadb-replica",
	'dbname' => 'my_database',
	'user' => 'root',
	'password' => 'main_root_password',
	'type' => "mysql",
	'flags' => DBO_DEFAULT,
	'max lag' => 60,
	'load' => 1,
];
// Integration tests fail when run with replication, due to not having the temporary tables.
if ( !defined( 'MW_PHPUNIT_TEST' ) ) {
	$wgDBservers = [ $dockerMainDb, $dockerReplicaDb ];
} else {
	$wgDBserver = $dockerMainDb['host'];
	$wgDBuser = $dockerMainDb['user'];
	$wgDBpassword = $dockerMainDb['password'];
	$wgDBtype = $dockerMainDb['type'];
}

Simulating replication lag

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On the replica database (e.g. docker compose exec mariadb-replica mariadb -u root -p):

STOP REPLICA;
CHANGE MASTER TO MASTER_DELAY=$n;
START REPLICA;

where $n is the number of seconds to delay. Set this to 0 to remove the lag.

You can check the amount of lag by running SHOW REPLICA STATUS\G; and looking for the row SQL_Delay.

Postgres (single database server)

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These instruction assume a new installation (no LocalSettings.php).

docker-compose.override.yml
services:
  database:
    image: postgres
    environment:
      POSTGRES_PASSWORD: example
    volumes:
      - dbdata:/var/lib/postgresql/data
volumes:
  dbdata:
    driver: local

To install the MediaWiki database tables, use:

docker compose exec mediawiki php maintenance/install.php --dbuser postgres --dbpass example --dbserver database --dbtype postgres --lang en --pass dockerpass mediawiki admin