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 indispensable for the big data ecosystem. This topic describes how to synchronize data from an Apsara PolarDB for MySQL cluster to a user-created Kafka cluster by using Data Transmission Service (DTS). The data synchronization feature allows you to extend message processing capabilities.

Prerequisites

  • The version of the user-created Kafka cluster is 0.10 or 1.0.
  • A topic is created in the Kafka cluster to receive the synchronized data.
  • The binary logging feature is enabled for the Apsara PolarDB for MySQL cluster. For more information, see Enable binary logging.

Precautions

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 automatically update the objects to be synchronized based on their names.
    Note 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 modify the objects to be synchronized. For more information, see Add an object to a data synchronization task.

Data format

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

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 procedure.
    Note On the buy page, set Source Instance to PolarDB, set Target Instance to Kafka, and set Synchronization Topology to One-Way Synchronization.
  2. Log on to 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 the destination instance resides.
    Select a region
  5. Find the data synchronization instance and click Configure Synchronization Channel in the Actions column.
  6. 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 The value of this parameter is set to PolarDB Instance and cannot be changed.
    Instance Region The region of the source instance. The region is the same as the source region that you selected when you purchased the data synchronization instance. You cannot change the value of this parameter.
    PolarDB Instance ID Select the ID of the source PolarDB cluster.
    Database Account Enter the database account of the source PolarDB cluster. The account must have the REPLICATION SLAVE permission, the REPLICATION CLIENT permission, and the permission to perform SELECT operations on the required objects.
    Database Password Enter the password of the source database account.
    Destination Instance Details Instance Type
    • If the Kafka cluster is deployed on an ECS instance, select User-Created Database in ECS Instance
    • If the Kafka cluster is deployed on a local server, select User-Created Database Connected over Express Connect, VPN Gateway, or Smart Access Gateway.
      Note If you select User-Created Database Connected over Express Connect, VPN Gateway, or Smart Access Gateway, you must specify the VPC ID, IP address, and port number.
    Instance Region The region of the destination instance. The region is the same as the destination region that you selected when you purchased the data synchronization instance. 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 the authentication is disabled for the Kafka cluster, you do not need to enter the username.
    Database Password Enter the password of the username. If the authentication is disabled for the Kafka cluster, you do not need to enter the password.
    Topic
    1. Click Get Topic List.
    2. 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.
  7. In the lower-right corner of the page, click Set Whitelist and Next.
    Note DTS adds the CIDR blocks of DTS servers to the whitelist of the source PolarDB cluster and the inbound rule of the destination ECS instance. This ensures that DTS servers can connect to the source cluster and destination instance.
  8. Configure the processing mode in existing destination tables and the objects to be synchronized.
    Configure the processing mode and objects
    Parameter Description
    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
    • You can select only tables as the objects to be synchronized.
    • After an object is synchronized to the destination database, the name of the object remains unchanged. You can change the names of the objects that are synchronized to the destination database by using the object name mapping feature. For more information about how to use this feature, see Specify the name of an object in the destination instance.
  9. In the lower-right corner of the page, click Next.
  10. In the lower-right corner of the page, click Precheck.
    Note
    • Before you can start the data synchronization task, a precheck is performed. 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 the precheck again.
  11. Close the Precheck dialog box after the following message is displayed: The precheck is passed.
  12. Wait until the initial synchronization is complete and the data synchronization task is in the Synchronizing state.
    On the Synchronization Tasks page, view the status of the data synchronization task.View the status of a data synchronization task.