Kafka Connect - Streamlining Data Integration

Thursday. February 27, 2025 - 3 mins

What is Kafka Connect?

Kafka Connect is a system designed to simplify data integration by facilitating the movement of data between Kafka and external systems. Instead of manually writing producers or consumers for each integration, Kafka Connect provides a ready-to-use framework that requires only configuration.

Why Use Kafka Connect?

When needing to send data to multiple applications, connecting the data source directly to a Kafka broker allows consumers to retrieve messages from there. Typically, data producers can be integrated in two ways:

1. The producer runs inside the originating application, fetching data from the database and sending it to the Kafka cluster.
2. If the source application’s code is unavailable or modifying it is impractical, an independent Kafka producer is created to connect directly to the database and send the data.

Both approaches work, but Kafka Connect offers a simpler alternative.

How Kafka Connect Works

Kafka Connect acts as an intermediary between data sources and Kafka clusters, as well as between Kafka clusters and target systems. This means:

• Source Connector: Moves data from the source database to Kafka.
• Sink Connector: Moves data from Kafka to a target database.

Kafka Connect provides out-of-the-box data integration capabilities without writing a single line of code—only configuration is needed.

How Is Kafka Connect So Flexible?

Kafka Connect supports a variety of systems, including relational and NoSQL databases, Salesforce, Teradata, Elasticsearch, Twitter, and file systems. This flexibility is possible due to the Kafka Connect Framework, which consists of:

• Source Connector & SourceTask: Fetches data from an external source.
• Sink Connector & SinkTask: Writes data to an external system.

By using this framework, developers can write custom connectors, package them as a JAR or ZIP archive, and deploy them within Kafka Connect. However, many pre-built connectors (e.g., JDBC) already exist, making it easy to install and configure connectors without additional coding.

Kafka Connect Scalability

Kafka Connect is itself a cluster, with each individual unit called a Connect Worker. A cluster consists of multiple workers, forming a fault-tolerant and scalable system:

• Tasks can be distributed among multiple workers.
• The number of tasks can be adjusted dynamically.
• A single Kafka Connect cluster can run both source and sink connectors simultaneously.
• Workers can be added dynamically without stopping existing connectors.

Kafka Connect Processing and Transformations

Kafka Connect was designed primarily for data movement, but it also allows Single Message Transformations (SMTs). These lightweight transformations can be applied to both source and sink connectors, enabling:

• Adding new fields using static data or metadata.
• Filtering or renaming fields.
• Masking sensitive fields.
• Changing record keys.
• Routing records to different Kafka topics.

Kafka Connect Architecture

Kafka Connect consists of three core components:

1. Worker: Runs and manages connectors and tasks.
2. Connector: Defines the logic for how data should be fetched or written.
3. Task: Executes the data movement operations.

Fault Tolerance & Load Balancing

Workers with the same group ID form a Kafka Connect Cluster, offering:

• High availability: If a worker crashes, tasks are reassigned to other workers.
• Scalability: New workers automatically balance the workload.

Deploying Kafka Connect

To deploy a connector:

1. Download and install the appropriate source/sink connector.
2. Configure the connector by specifying:
   • Database connection details.
   • Tables to copy.
   • Polling frequency.
   • Maximum number of tasks.
3. Start the connector using the command line or Kafka Connect REST API.
4. The worker starts the connector, determines the level of parallelism, and assigns tasks across available workers.
5. Tasks connect to external systems, poll data, and pass records to Kafka.

In the case of a Sink Task, records from Kafka are retrieved by the worker and written to the target system by the task.

Key Takeaways

• Kafka Connect eliminates the need for custom producers/consumers by providing pre-built connectors.
• It scales dynamically by adding more workers and tasks.
• It supports fault tolerance and automatic load balancing.
• Single Message Transformations (SMTs) allow minor data modifications during transfer.
• Workers handle record transfer, while tasks handle external system interactions.
• Kafka Connect is a reusable, out-of-the-box solution for data integration.

Kafka Connect is a powerful tool for organizations looking to simplify their data ingestion and export pipelines while maintaining scalability and flexibility. 🚀

Lais Ziegler

Dev in training... 👋

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