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The Apache Kafka event source brings messages into Knative. It reads events from an Apache Kafka cluster and passes these events to an event sink so that they can be consumed. You can use the KafkaSource event source with OpenShift Serverless.

Creating a Kafka event source by using the web console

You can create and verify a Kafka event source from the OpenShift Container Platform web console.

Prerequisites
  • The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka custom resource are installed on your cluster.

  • You have logged in to the web console.

  • You are in the Developer perspective.

  • You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform.

Procedure
  1. Navigate to the Add page and select Event Source.

  2. In the Event Sources page, select Kafka Source in the Type section.

  3. Configure the Kafka Source settings:

    1. Add a comma-separated list of Bootstrap Servers.

    2. Add a comma-separated list of Topics.

    3. Add a Consumer Group.

    4. Select the Service Account Name for the service account that you created.

    5. Select the Sink for the event source. A Sink can be either a Resource, such as a channel, broker, or service, or a URI.

    6. Enter a Name for the Kafka event source.

  4. Click Create.

Verification steps

You can verify that the Kafka event source was created and is connected to the sink by viewing the Topology page.

  1. In the Developer perspective, navigate to Topology.

  2. View the Kafka event source and sink.

    View the Kafka source and service in the Topology view

Creating a Kafka event source by using YAML

You can create a Kafka event source by using YAML.

Prerequisites
  • The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka custom resource are installed on your cluster.

  • You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform.

Procedure
  1. Create a YAML file containing the following:

    apiVersion: sources.knative.dev/v1beta1
    kind: KafkaSource
    metadata:
      name: <source-name>
    spec:
      consumerGroup: <group-name> (1)
      bootstrapServers:
      - <list-of-bootstrap-servers>
      topics:
      - <list-of-topics> (2)
      sink:
    1 A consumer group is a group of consumers that use the same group ID, and consume data from a topic.
    2 A topic provides a destination for the storage of data. Each topic is split into one or more partitions.
    Example KafkaSource object
    apiVersion: sources.knative.dev/v1beta1
    kind: KafkaSource
    metadata:
      name: kafka-source
    spec:
      consumerGroup: knative-group
      bootstrapServers:
      - my-cluster-kafka-bootstrap.kafka:9092
      topics:
      - knative-demo-topic
      sink:
        ref:
          apiVersion: serving.knative.dev/v1
          kind: Service
          name: event-display
  2. Apply the YAML file:

    $ oc apply -f <filename>

Additional resources