Outbound Replication from Replicated Transactions to MariaDB Server

Overview

MariaDB SkySQL customers can configure outbound replication from a Replicated Transactions service to MariaDB Server.

For additional information about the stored procedures used to configure replication with Replicated Transactions services, see "SkySQL Replication Helper Procedures for Replicated Transactions".

Use Cases

  • Offsite replica for Disaster Recovery (DR)

  • Dedicated replica for reporting workloads

Compatibility

  • Replicated Transactions

Requirements

To configure outbound replication from your Replicated Transactions service in SkySQL to an external replica server using MariaDB Server, the following requirements must be met:

  • The external replica server must use a supported version of MariaDB Server, and the external replica server must use a version in the same or newer release series as the version used by the SkySQL service.

  • When the SkySQL service uses ES 10.6, the following versions are supported for the external replica server:

    • MariaDB Server 10.6

  • When the SkySQL service uses ES 10.5, the following versions are supported for the external replica server:

    • MariaDB Server 10.5

    • MariaDB Server 10.6

  • When the SkySQL service uses ES 10.4, the following versions are supported for the external replica server:

    • MariaDB Server 10.4

    • MariaDB Server 10.5

    • MariaDB Server 10.6

Request User for Outbound Replication

On the SkySQL Customer Portal, create a support case to request a user account with sufficient privileges for outbound replication to the external replica server.

SkySQL customers do not have sufficient privileges to create a user account that supports replication, so the user account must be created by SkySQL Support.

Check User Account

On the SkySQL service, confirm that the new user has sufficient privileges by executing SHOW GRANTS:

SHOW GRANTS FOR 'external_replication'@'%';
+------------------------------------------------------------------------------------------------------------------------------------------------+
| Grants for external_replication@%                                                                                                              |
+------------------------------------------------------------------------------------------------------------------------------------------------+
| GRANT REPLICATION SLAVE, SLAVE MONITOR ON *.* TO `external_replication`@`%` IDENTIFIED BY PASSWORD '*CCD3A959D6A004B9C3807B728BC2E55B67E10518' |
+------------------------------------------------------------------------------------------------------------------------------------------------+

Add External Replica to Allowlist

On the SkySQL Customer Portal, add the IP address of the external replica server to the SkySQL service's allowlist.

Obtain GTID Position

On the SkySQL service, obtain the GTID position from which to start replication.

When you want to start replication from the most recent transaction, the current GTID position can be obtained by querying the value of the gtid_current_pos system variable with the SHOW GLOBAL VARIABLES statement:

SHOW GLOBAL VARIABLES
   LIKE 'gtid_current_pos';
+------------------+-------------------+
| Variable_name    | Value             |
+------------------+-------------------+
| gtid_current_pos | 435700-435700-124 |
+------------------+-------------------+

Configure GTID Position

On the external replica server, configure the GTID position from which to start replication.

The GTID position can be configured by setting the gtid_slave_pos system variable with the SET GLOBAL statement:

SET GLOBAL gtid_slave_pos='435700-435700-124';

Download SkySQL CA Chain

On the external replica server, download the SkySQL CA chain.

Configure Replication

On the external replica server, configure replication using the connection parameters for your MariaDB SkySQL service.

Replication can be configured using the CHANGE MASTER TO statement:

CHANGE MASTER TO
   MASTER_HOST='FULLY_QUALIFIED_DOMAIN_NAME',
   MASTER_PORT=TCP_PORT,
   MASTER_USER='external_replication',
   MASTER_PASSWORD='my_password',
   MASTER_SSL=1,
   MASTER_SSL_CA='~/PATH_TO_PEM_FILE',
   MASTER_USE_GTID=slave_pos;
  • Replace FULLY_QUALIFIED_DOMAIN_NAME with the Fully Qualified Domain Name of your service

  • Replace TCP_PORT with the read-write or read-only port of your service

  • Replace ~/PATH_TO_PEM_FILE with the path to the certificate authority chain (.pem) file

Start Replication

On the external replica server, start replication.

Replication can be started using the START REPLICA statement:

START REPLICA;

Check Replication Status

On the external replica server, check replication status.

Replication status can be checked using the SHOW REPLICA STATUS statement:

SHOW REPLICA STATUS\G
*************************** 1. row ***************************
                Slave_IO_State: Waiting for master to send event
                   Master_Host: my-service.mdb0002147.db.skysql.net
                   Master_User: external_replication
                   Master_Port: 5003
                 Connect_Retry: 60
               Master_Log_File: mariadb-bin.000001
           Read_Master_Log_Pos: 558
                Relay_Log_File: mariadb-relay-bin.000002
                 Relay_Log_Pos: 674
         Relay_Master_Log_File: mariadb-bin.000001
              Slave_IO_Running: Yes
             Slave_SQL_Running: Yes
               Replicate_Do_DB:
           Replicate_Ignore_DB:
            Replicate_Do_Table:
        Replicate_Ignore_Table:
       Replicate_Wild_Do_Table:
   Replicate_Wild_Ignore_Table:
                    Last_Errno: 0
                    Last_Error:
                  Skip_Counter: 0
           Exec_Master_Log_Pos: 558
               Relay_Log_Space: 985
               Until_Condition: None
                Until_Log_File:
                 Until_Log_Pos: 0
            Master_SSL_Allowed: Yes
            Master_SSL_CA_File: /var/lib/mysql/skysql_chain.pem
            Master_SSL_CA_Path:
               Master_SSL_Cert:
             Master_SSL_Cipher:
                Master_SSL_Key:
         Seconds_Behind_Master: 0
 Master_SSL_Verify_Server_Cert: No
                 Last_IO_Errno: 0
                 Last_IO_Error:
                Last_SQL_Errno: 0
                Last_SQL_Error:
   Replicate_Ignore_Server_Ids:
              Master_Server_Id: 435701
                Master_SSL_Crl: /var/lib/mysql/skysql_chain.pem
            Master_SSL_Crlpath:
                    Using_Gtid: Slave_Pos
                   Gtid_IO_Pos: 435700-435700-127
       Replicate_Do_Domain_Ids:
   Replicate_Ignore_Domain_Ids:
                 Parallel_Mode: optimistic
                     SQL_Delay: 0
           SQL_Remaining_Delay: NULL
       Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
              Slave_DDL_Groups: 0
Slave_Non_Transactional_Groups: 0
    Slave_Transactional_Groups: 0