Data Transmission Service:Synchronize MySQL on ECS to Kafka

Usage notes

• During initial full data synchronization, DTS consumes read and write resources from the source and destination databases, which increases the database load. If database performance is poor, instance specifications are low, or business traffic is heavy (for example, the source database has many slow SQL queries or tables without primary keys, or the destination database experiences deadlocks), the database load increases and may even cause the service to become unavailable. Before you synchronize data, evaluate the performance of your source and destination instances. We recommend performing data synchronization during off-peak hours, for example, when the CPU utilization of both instances is below 30%.

• If a source table lacks a primary key or unique constraint, and no combination of its columns is unique, duplicate data may be written to the destination database.

Billing

Limitations

• Only tables can be synchronized. Other object types are not supported.
• Automatic adjustment of synchronization objects is not supported. If you rename a synchronized table and the new name is not included in the list of synchronization objects, data from that table is no longer synchronized to the destination Kafka cluster. To continue synchronizing the renamed table, you must Reselect Objects. For more information, see Add synchronization objects.

Supported synchronization topologies

• One-way one-to-one synchronization
• One-way one-to-many synchronization
• One-way many-to-one synchronization
• One-way cascade synchronization

Before you begin

Before you configure a data synchronization task, create an account for the self-managed MySQL database and configure binary logging.

Procedure

1. Purchase a data synchronization task. For more information, see Purchase procedure.
   Note When you purchase the task, set the source instance to MySQL, the destination instance to Kafka, and the synchronization topology to One-way Synchronization.
2. Log on to the DTS console.
   Note If the DTS console automatically redirects you to the Data Management (DMS) console, move the pointer over the icon in the lower-right corner and click to return to the previous version of the DTS console.

3. In the left-side navigation pane, click Data Synchronization.

4. At the top of the Synchronization Tasks page, select the region where your destination instance is located.

5. Find the data synchronization task that you purchased and click Configure Task.

6. Configure the source and destination instances for the synchronization channel.
   

   Category	Setting	Description
   N/A	Synchronization Task Name	DTS automatically generates a task name. You can specify a descriptive name for easy identification. The name does not need to be unique.
   Source instance details	instance type	Select self-managed database on an ECS instance.
   	instance region	The region of the source instance. This value was determined when you purchased the data synchronization task and cannot be changed.
   	ECS instance ID	Select the ID of the ECS instance that hosts the source database.
   	database type	Set to MySQL and cannot be changed.
   	Port	The service port of the self-managed database. Default value: 3306.
   	Database Account	Enter the database account for the self-managed MySQL database. The account must have the REPLICATION CLIENT, REPLICATION SLAVE, SHOW VIEW, and SELECT permissions on the objects to be synchronized.
   	Database Password	Enter the password for the database account.
   Destination instance details	instance type	Select a value based on where the Kafka cluster is deployed. In this example, self-managed database on an ECS instance is selected. Note If you select a different instance type, you must complete the required preparations. For more information, see Overview of preparations.
   	instance region	The region of the destination instance. This value was determined when you purchased the data synchronization task and cannot be changed.
   	ECS instance ID	Select the ID of the ECS instance where the Kafka cluster is deployed.
   	database type	Select Kafka.
   	Port	The service port of the Kafka cluster. Default value: 9092.
   	Database Account	Enter the username for the Kafka cluster. Leave this field empty if the cluster does not require authentication.
   	Database Password	Enter the password for the username. Leave this field empty if the cluster does not require authentication.
   	Topic	Click Get Topic List on the right and select a topic name from the drop-down list.
   	Kafka version	Select the version of the destination Kafka cluster.
   	connection method	Based on your business and security requirements, select Non-encrypted or SCRAM-SHA-256.

7. In the lower-right corner of the page, click Set Whitelist and Next.

   If the source or destination database is an Alibaba Cloud database instance, such as an ApsaraDB RDS for MySQL or ApsaraDB for MongoDB instance, DTS automatically adds the CIDR blocks of DTS servers to the IP address whitelist of the instance. If the source or destination database is a self-managed database hosted on an Elastic Compute Service (ECS) instance, DTS automatically adds the CIDR blocks of DTS servers to the security group rules of the ECS instance, and you must make sure that the ECS instance can access the database. If the self-managed database is hosted on multiple ECS instances, you must manually add the CIDR blocks of DTS servers to the security group rules of each ECS instance. If the source or destination database is a self-managed database that is deployed in a data center or provided by a third-party cloud service provider, you must manually add the CIDR blocks of DTS servers to the IP address whitelist of the database to allow DTS to access the database. For more information, see Whitelist DTS server IP addresses.

   Warning

   Adding the public IP address blocks of the DTS service, either automatically or manually, may pose security risks. Using this product, you acknowledge that you understand and accept the potential security risks and that you must implement basic security measures. These measures include, but are not limited to, strengthening password security, limiting the ports open to each CIDR block, using authentication for internal API calls, and regularly checking and restricting unnecessary CIDR blocks. Alternatively, you can connect through a private network using a leased line, VPN Gateway, or Smart Access Gateway.

8. Configure the synchronization objects.

   Parameter	Description
   Data Format in Kafka	Data synchronized to the Kafka cluster is stored in Avro or Canal JSON format. For more information, see Data formats in a message queue.
   Policy for shipping data to Kafka partitions	Select the policy that meets your business requirements. For a detailed description, see Policies for synchronizing data to Kafka partitions.
   Synchronization objects	In the Source Objects box, select the objects to synchronize (tables are the finest granularity), and then click the icon to move them to the Selected box. Note DTS automatically maps the table name to the topic name that you selected in Step 6. To change the destination topic for a table, use the object name mapping feature. For more information, see Set object names in the destination instance.
   Object name mapping	Change the names of synchronized objects in the destination instance. For more information, see Map databases, tables, and columns.
   Retry time for failed connections	If DTS cannot connect to the source or destination instance, it retries for 720 minutes (12 hours) by default. You can also specify a custom retry duration. If DTS reconnects to the source or destination instance within the specified duration, the synchronization task automatically resumes. Otherwise, the task fails. Note You are billed for task run time during connection retries. Customize the retry duration based on your business needs, or release the DTS instance as soon as the source and destination instances are released.

9. After you complete the preceding configurations, click Next in the lower-right corner of the page.
10. Configure advanced settings for initial synchronization.

    Parameter	Description
    Initial synchronization	By default, both Initial Schema Synchronization and Initial Full Data Synchronization are selected. Before synchronizing incremental data, DTS synchronizes the schema and existing data of the selected objects to the destination.
    Filter options	By default, Ignore DDL in incremental synchronization phase is selected. This means that DTS does not synchronize DDL operations performed on the source database during incremental data synchronization.

11. After completing the preceding configurations, click Precheck and Start in the lower-right corner of the page.

    Note

    • A precheck runs before the synchronization task starts, and you can only start the task after it passes.

    • If the precheck fails, click the icon next to the failed item to view the details.

      • You can fix the issues based on the cause and run the precheck again.

      • If you do not need to fix the items that triggered warnings, you can click Ignore or Ignore Warnings and Rerun Precheck to skip the warnings and run the precheck again.

12. After the Precheck dialog box shows Precheck Passed, close the Precheck dialog box. The data synchronization task starts.
    On the Data Synchronization page, the task list displays key information, including Instance ID/Task Name, Status (for example, Synchronizing), Synchronization Overview (including latency and speed), Billing Method, and Synchronization Topology. The Actions column provides options such as Pause Synchronization, Convert to Subscription, and Upgrade.