Kafka is a distributed message queue service that features high throughput and high scalability. Kafka is widely used for big data analytics such as log collection, data aggregation, streaming processing, and online and offline analysis. It is important for the big data ecosystem. This topic describes how to synchronize data from an ApsaraDB RDS for MySQL instance to a user-created Kafka cluster by using Data Transmission Service (DTS). The data synchronization feature allows you to extend message processing capabilities.

Prerequisites

Precautions

  • DTS uses read and write resources of the source and destination databases during initial full data synchronization. This may increase the loads of the database servers. If the database performance is unfavorable, the specification is low, or the data volume is large, database services may become unavailable. For example, DTS occupies a large amount of read and write resources in the following cases: a large number of slow SQL queries are performed on the source database, the tables have no primary keys, or a deadlock occurs in the destination database. Before you synchronize data, evaluate the impact of data synchronization on the performance of the source and destination databases. We recommend that you synchronize data during off-peak hours. For example, you can synchronize data when the CPU utilization of the source and destination databases is less than 30%.
  • The source database must have PRIMARY KEY or UNIQUE constraints and all fields must be unique. Otherwise, the destination database may contain duplicate data records.

Limits

  • You can select only tables as the objects to be synchronized.
  • DTS does not synchronize the data in a renamed table to the destination Kafka cluster. This applies if the new table name is not included in the objects to be synchronized. To synchronize the data in a renamed table to the destination Kafka cluster, you must reselect the objects to be synchronized. For more information, see Add an object to a data synchronization task.

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

Data format

The data that is synchronized to the Kafka cluster is stored in the Avro format. For more information, see DTS Avro schema.

Note After the data is synchronized to the Kafka cluster, you must parse the data based on the Avro schema.

Procedure

  1. Purchase a data synchronization instance. For more information, see Purchase a DTS instance.
    Note On the buy page, set Source Instance to MySQL, set Target Instance to Kafka, and set Synchronization Topology to One-Way Synchronization.
  2. Configure the source and destination instances.
    Configure the source and destination instances
    Section Parameter Description
    N/A Synchronization Task Name DTS automatically generates a task name. We recommend that you specify an informative name for easy identification. You do not need to use a unique task name.
    Source Instance Details Instance Type Select RDS Instance.
    Instance Region The region of the source instance. The region is the same as the source region that you selected on the buy page. You cannot change the value of this parameter.
    Instance ID Select the ID of the source RDS instance.
    Database Account Enter the account that is used to connect to the source database. The account must have the SELECT permission on the required objects, the REPLICATION CLIENT permission, the REPLICATION SLAVE permission, and the SHOW VIEW permission.
    Database Password Enter the password of the source database account.
    Encryption Select Non-encrypted or SSL-encrypted. If you want to select SSL-encrypted, you must enable SSL encryption for the RDS instance before you configure the data synchronization task. For more information, see Configure SSL encryption on an ApsaraDB RDS for MySQL instance.
    Notice The Encryption parameter is available only for regions in mainland China and the China (Hong Kong) region.
    Destination Instance Details Instance Type Select an instance type based on the deployment of the Kafka cluster. In this example, select User-Created Database in ECS Instance.
    Note If you select other instance types, you must prepare the environment that is required for the Kafka cluster. For more information, see Preparation overview.
    Instance Region The region of the destination cluster. The region is the same as the destination region that you selected on the buy page. You cannot change the value of this parameter.
    ECS Instance ID Select the ID of the ECS instance on which the Kafka cluster is deployed.
    Database Type Select Kafka.
    Port Number Enter the service port number of the Kafka cluster. The default port number is 9092.
    Database Account Enter the username that is used to log on to the Kafka cluster. If no authentication is enabled for the Kafka cluster, you do not need to enter the username.
    Database Password Enter the password of the username. If no authentication is enabled for the Kafka cluster, you do not need to enter the password.
    Topic Click Get Topic List, and select a topic name from the drop-down list.
    Kafka Version Select the version of the destination Kafka cluster.
    Encryption Select Non-encrypted or SCRAM-SHA-256 based on your business and security requirements.
  3. In the lower-right corner of the page, click Set Whitelist and Next.
  4. Select the objects to be synchronized.
    Select the objects to be synchronized
    Setting Description
    Select the objects to be synchronized Select tables from the Available section and click the Right arrow icon to move the tables to the Selected section.
    Note DTS maps the table names to the topic name that you select in Step 6. If you want to change the topic, you can use the object name mapping feature. For more information, see Specify the name of an object in the destination instance.
  5. In the lower-right corner of the page, click Next.
  6. Configure initial synchronization.
    Kafka: Configure initial synchronization
    Parameter Description
    Initial Synchronization Select both Initial Schema Synchronization and Initial Full Data Synchronization. DTS synchronizes the schemas and historical data of the required objects and then synchronizes incremental data.
    Filter options Ignore DDL in incremental synchronization phase is selected by default. In this case, DTS does not synchronize DDL operations that are performed on the source database during incremental data synchronization.
  7. In the lower-right corner of the page, click Precheck.
    Note
    • Before you can start the data synchronization task, DTS performs a precheck. You can start the data synchronization task only after the task passes the precheck.
    • If the task fails to pass the precheck, click the Info icon icon next to each failed item to view details. Troubleshoot the issues based on the causes and run a precheck again.
  8. Close the Precheck dialog box after the following message is displayed: The precheck is passed. Then, the data synchronization task starts.
    You can view the status of the data synchronization task on the Synchronization Tasks page.View the status of a data synchronization task