Configuring binary log file position replication with an external source instance

You can set up replication between an RDS for MySQL or MariaDB DB instance and a MySQL or MariaDB instance that is external to Amazon RDS using binary log file replication.

Before you begin

You can configure replication using the binary log file position of replicated transactions.

The permissions required to start replication on an Amazon RDS DB instance are restricted and not available to your Amazon RDS master user. Because of this, make sure that you use the Amazon RDS mysql.rds_set_external_master and mysql.rds_start_replication commands to set up replication between your live database and your Amazon RDS database.

To set the binary logging format for a MySQL or MariaDB database, update the binlog_format parameter. If your DB instance uses the default DB instance parameter group, create a new DB parameter group to modify binlog_format settings. We recommend that you use the default setting for binlog_format, which is MIXED. However, you can also set binlog_format to ROW or STATEMENT if you need a specific binary log (binlog) format. Reboot your DB instance for the change to take effect.

For information about setting the binlog_format parameter, see Configuring RDS for MySQL binary logging. For information about the implications of different MySQL replication types, see Advantages and disadvantages of statement-based and row-based replication in the MySQL documentation.

Note

Starting with RDS for MySQL version 8.0.36, Amazon RDS doesn't replicate the mysql database. Therefore, if there are users on the external database that you need on the Amazon RDS replica, make sure to create them manually.

Configuring binary log file position replication with an external source instance

Follow these guidelines when you set up an external source instance and a replica on Amazon RDS:

• Monitor failover events for the Amazon RDS DB instance that is your replica. If a failover occurs, then the DB instance that is your replica might be recreated on a new host with a different network address. For information on how to monitor failover events, see Working with Amazon RDS event notification.

• Maintain the binlogs on your source instance until you have verified that they have been applied to the replica. This maintenance makes sure that you can restore your source instance in the event of a failure.

• Turn on automated backups on your Amazon RDS DB instance. Turning on automated backups makes sure that you can restore your replica to a particular point in time if you need to re-synchronize your source instance and replica. For information on backups and point-in-time restore, see Backing up, restoring, and exporting data.

To configure binary log file replication with an external source instance

1. Make the source MySQL or MariaDB instance read-only.

   mysql> FLUSH TABLES WITH READ LOCK;
   mysql> SET GLOBAL read_only = ON; 

2. Run the SHOW MASTER STATUS command on the source MySQL or MariaDB instance to determine the binlog location.

   You receive output similar to the following example.

   File                        Position  
   ------------------------------------
    mysql-bin-changelog.000031      107   
   ------------------------------------ 

3. Copy the database from the external instance to the Amazon RDS DB instance using mysqldump. For very large databases, you might want to use the procedure in Importing data to an Amazon RDS MariaDB or MySQL database with reduced downtime.

   For Linux, macOS, or Unix:

   mysqldump --databases database_name \
       --single-transaction \
       --compress \
       --order-by-primary \
       -u local_user \
       -plocal_password | mysql \
           --host=hostname \
           --port=3306 \
           -u RDS_user_name \
           -pRDS_password

   For Windows:

   mysqldump --databases database_name ^
       --single-transaction ^
       --compress ^
       --order-by-primary ^
       -u local_user ^
       -plocal_password | mysql ^
           --host=hostname ^
           --port=3306 ^
           -u RDS_user_name ^
           -pRDS_password

   Note

   Make sure that there isn't a space between the -p option and the entered password.

   To specify the host name, user name, port, and password to connect to your Amazon RDS DB instance, use the --host, --user (-u), --port and -p options in the mysql command. The host name is the Domain Name Service (DNS) name from the Amazon RDS DB instance endpoint, for example myinstance.123456789012.us-east-1.rds.amazonaws.com. You can find the endpoint value in the instance details in the AWS Management Console.

4. Make the source MySQL or MariaDB instance writeable again.

   mysql> SET GLOBAL read_only = OFF;
   mysql> UNLOCK TABLES; 

   For more information on making backups for use with replication, see the MySQL documentation.

5. In the AWS Management Console, add the IP address of the server that hosts the external database to the virtual private cloud (VPC) security group for the Amazon RDS DB instance. For more information on modifying a VPC security group, see Security groups for your VPC in the Amazon Virtual Private Cloud User Guide.

   The IP address can change when the following conditions are met:

   • You are using a public IP address for communication between the external source instance and the DB instance.

   • The external source instance was stopped and restarted.

   If these conditions are met, verify the IP address before adding it.

   You might also need to configure your local network to permit connections from the IP address of your Amazon RDS DB instance. You do this so that your local network can communicate with your external MySQL or MariaDB instance. To find the IP address of the Amazon RDS DB instance, use the host command.

   host db_instance_endpoint

   The host name is the DNS name from the Amazon RDS DB instance endpoint.

6. Using the client of your choice, connect to the external instance and create a user to use for replication. Use this account solely for replication and restrict it to your domain to improve security. The following is an example.

   CREATE USER 'repl_user'@'mydomain.com' IDENTIFIED BY 'password';

   Note

   Specify a password other than the prompt shown here as a security best practice.

7. For the external instance, grant REPLICATION CLIENT and REPLICATION SLAVE privileges to your replication user. For example, to grant the REPLICATION CLIENT and REPLICATION SLAVE privileges on all databases for the 'repl_user' user for your domain, issue the following command.

   GRANT REPLICATION CLIENT, REPLICATION SLAVE ON *.* TO 'repl_user'@'mydomain.com';

8. Make the Amazon RDS DB instance the replica. To do so, first connect to the Amazon RDS DB instance as the master user. Then identify the external MySQL or MariaDB database as the source instance by using the mysql.rds_set_external_master command. Use the master log file name and master log position that you determined in step 2. The following is an example.

   CALL mysql.rds_set_external_master ('mymasterserver.mydomain.com', 3306, 'repl_user', 'password', 'mysql-bin-changelog.000031', 107, 0);

   Note

   On RDS for MySQL, you can choose to use delayed replication by running the mysql.rds_set_external_master_with_delay stored procedure instead. On RDS for MySQL, one reason to use delayed replication is to turn on disaster recovery with the mysql.rds_start_replication_until stored procedure. Currently, RDS for MariaDB supports delayed replication but doesn't support the mysql.rds_start_replication_until procedure.

9. On the Amazon RDS DB instance, issue the mysql.rds_start_replication command to start replication.

   CALL mysql.rds_start_replication;