Kafka is a distributed message queue service that features high throughput and high scalability. Kafka is widely used in big data fields such as log collection, monitoring data aggregation, streaming data processing, and online and offline analysis. It is indispensable 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). This allows you to extend message processing capabilities.

Prerequisites

  • The version of the user-created Kafka cluster is 0.10 or 1.0.
  • An ApsaraDB RDS for MySQL instance is created. For more information, see A new version is available..

Precautions

  • DTS uses read and write resources of the source and destination databases during initial full data synchronization. This may increase the database load. 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 synchronizing data, you must evaluate 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 usage 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, duplicate data may exist in the destination database.

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 modify 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.

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

Billing

For more information, see Pricing.

Procedure

  1. Purchase a data synchronization instance. For more information, see Purchase procedure.
    Note On the buy page, set Source Instance to MySQL, 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 Select RDS Instance.
    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.
    Instance ID Select the ID of the source RDS instance.
    Database Account Enter the database account of the source RDS instance. The account must have the REPLICATION SLAVE permission, the REPLICATION CLIENT permission, the SHOW VIEW permission, and the permission to perform SELECT operations on the required objects.
    Database Password Enter the password for the database account of the source RDS instance.
    Encryption Select Non-encrypted or SSL-encrypted. If you want to select SSL-encrypted, you must enable SSL encryption for the RDS instance before configuring the data synchronization task. For more information, see Configure SSL encryption for an RDS for MySQL instance.
    Notice The Encryption parameter is available only for regions in mainland China and the Hong Kong (China) region.
    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 for the username. If the authentication is disabled for the Kafka cluster, you do not need to enter the password.
    Topic
    1. Click the Get Topic List.
    2. Select a topic name from the drop-down list.
    Kafka Version Select a version based on 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.
  8. Select the objects to be synchronized.Select the objects to be synchronized
    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 DTS automatically maps the table names to the topic name that you select when you configure the source and destination instances. If you want to change the topic, you can move the pointer over the table and click Edit. You must specify a topic that exists in the Message Queue for Apache Kafka instance.
  9. In the lower-right corner of the page, click Next.
  10. Configure initial synchronization.Kafka: Configure initial synchronization
    Parameter Description
    Initial Synchronization Select both Initial Schema Synchronization and Initial Full Data Synchronization. Before synchronizing incremental data, DTS synchronizes the schemas and historical data of the required objects from the source database to the destination database.
    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.
  11. 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.
  12. 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.