21.6.5 Preparing the NDB Cluster for Replication
Preparing the NDB Cluster for replication consists of the following steps:
Check all MySQL servers for version compatibility (see Section 21.6.2, “General Requirements for NDB Cluster Replication”).
Create a replication account on the source Cluster with the appropriate privileges, using the following two SQL statements:
mysqlS> CREATE USER 'replica_user'@'replica_host' -> IDENTIFIED BY 'replica_password'; mysqlS> GRANT REPLICATION SLAVE ON *.* -> TO 'replica_user'@'replica_host';
In the previous statement,
replica_useris the replication account user name,
replica_hostis the host name or IP address of the replica, and
replica_passwordis the password to assign to this account.
mysqlS> CREATE USER 'myreplica'@'replica-host' -> IDENTIFIED BY '53cr37'; mysqlS> GRANT REPLICATION SLAVE ON *.* -> TO 'myreplica'@'replica-host';
For security reasons, it is preferable to use a unique user account—not employed for any other purpose—for the replication account.
mysqlR> CHANGE MASTER TO -> MASTER_HOST='source_host', -> MASTER_PORT=source_port, -> MASTER_USER='replica_user', -> MASTER_PASSWORD='replica_password';
In the previous statement,
source_hostis the host name or IP address of the replication source,
source_portis the port for the replica to use when connecting to the source,
replica_useris the user name set up for the replica on the source, and
replica_passwordis the password set for that user account in the previous step.
For example, to tell the replica to use the MySQL server whose host name is
rep-sourcewith the replication account created in the previous step, use the following statement:
mysqlR> CHANGE MASTER TO -> MASTER_HOST='rep-source', -> MASTER_PORT=3306, -> MASTER_USER='myreplica', -> MASTER_PASSWORD='53cr37';
For a complete list of options that can be used with this statement, see Section 184.108.40.206, “CHANGE MASTER TO Statement”.
To provide replication backup capability, you also need to add an
--ndb-connectstringoption to the replica's
my.cnffile prior to starting the replication process. See Section 21.6.9, “NDB Cluster Backups With NDB Cluster Replication”, for details.
For additional options that can be set in
my.cnffor replicas, see Section 16.1.6, “Replication and Binary Logging Options and Variables”.
If the source cluster is already in use, you can create a backup of the source and load this onto the replica to cut down on the amount of time required for the replica to synchronize itself with the source. If the replica is also running NDB Cluster, this can be accomplished using the backup and restore procedure described in Section 21.6.9, “NDB Cluster Backups With NDB Cluster Replication”.
In the event that you are not using NDB Cluster on the replica, you can create a backup with this command on the source:
shellS> mysqldump --master-data=1
Then import the resulting data dump onto the replica by copying the dump file over to it. After this, you can use the mysql client to import the data from the dumpfile into the replica database as shown here, where
dump_fileis the name of the file that was generated using mysqldump on the source, and
db_nameis the name of the database to be replicated:
shellR> mysql -u root -p db_name < dump_file
For a complete list of options to use with mysqldump, see Section 4.5.4, “mysqldump — A Database Backup Program”.Note
If you copy the data to the replica in this fashion, you should make sure that the replica is started with the
--skip-slave-startoption on the command line, or else include
skip-slave-startin the replica's
my.cnffile to keep it from trying to connect to the source to begin replicating before all the data has been loaded. Once the data loading has completed, follow the additional steps outlined in the next two sections.
Ensure that each MySQL server acting as a replication source is assigned a unique server ID, and has binary logging enabled, using the row-based format. (See Section 16.2.1, “Replication Formats”.) These options can be set either in the source server's
my.cnffile, or on the command line when starting the source mysqld process. See Section 21.6.6, “Starting NDB Cluster Replication (Single Replication Channel)”, for information regarding the latter option.