MariaDB Replication

Table of Contents

Master Slave Setup

Master Configuration

The MariaDB Server has to be accessible from outside. For Debian, one has to comment bind-address=127.0.0.1 in the file /etc/mysql/mariadb.conf.d/50-server.cnf.
If you have any firewall enabled, make sure to allow port 3306/TCP.

Add this segment at the end of /etc/mysql/my.cnf

[mariadb]
log-bin
server_id=1
log-basename=master
binlog-format=mixed

Restart mariadb now

Create a replication user

CREATE USER 'replication'@'%' IDENTIFIED BY '<password>';
GRANT REPLICATION SLAVE ON *.* TO 'replication'@'%';

Next we have to get the data necessary so the slave knows where to start replicating.

FLUSH TABLES WITH READ LOCK;
SHOW MASTER STATUS;

Do not close this session, keep it running until you have made the backup from the next step
# mysqldump -u root -p (db name) > db_name.sql

You can unlock the database again.
UNLOCK TABLES;

Slave Configuration

Edit your /etc/mysql/my.cnf file
Make sure to choose different IDs for every host

[mysqld]
server-id = 2

Create the database and restore the sql dumps made earlier.
# mysql -u root -p (db name) < db_name.sql

Set the database master now

CHANGE MASTER TO
  MASTER_HOST='<domain>',
  MASTER_USER='replication',
  MASTER_PASSWORD='<password>',
  MASTER_PORT=3306,
  MASTER_LOG_FILE='<master log file>',
  MASTER_LOG_POS=<master log position>,
  MASTER_CONNECT_RETRY=10,
  MASTER_USE_GTID = slave_pos;

Start slave now
START SLAVE;
And check the status
SHOW SLAVE STATUS \G

If both of the following options say yes, everything is working as intended

Slave_IO_Running: Yes
Slave_SQL_Running: Yes