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Kafka sinks are a type of event sink that are available if a cluster administrator has enabled Kafka on your cluster. You can send events directly from an event source to a Kafka topic by using a Kafka sink.

Using a Kafka sink

You can create an event sink called a Kafka sink that sends events to a Kafka topic. Creating Knative resources by using YAML files uses a declarative API, which enables you to describe applications declaratively and in a reproducible manner. By default, a Kafka sink uses the binary content mode, which is more efficient than the structured mode. To create a Kafka sink by using YAML, you must create a YAML file that defines a KafkaSink object, then apply it by using the oc apply command.

Prerequisites
  • The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka custom resource (CR) 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 Red Hat OpenShift Service on AWS.

  • You have access to a Red Hat AMQ Streams (Kafka) cluster that produces the Kafka messages you want to import.

  • Install the OpenShift CLI (oc).

Procedure
  1. Create a KafkaSink object definition as a YAML file:

    Kafka sink YAML
    apiVersion: eventing.knative.dev/v1alpha1
    kind: KafkaSink
    metadata:
      name: <sink-name>
      namespace: <namespace>
    spec:
      topic: <topic-name>
      bootstrapServers:
       - <bootstrap-server>
  2. To create the Kafka sink, apply the KafkaSink YAML file:

    $ oc apply -f <filename>
  3. Configure an event source so that the sink is specified in its spec:

    Example of a Kafka sink connected to an API server source
    apiVersion: sources.knative.dev/v1alpha2
    kind: ApiServerSource
    metadata:
      name: <source-name> (1)
      namespace: <namespace> (2)
    spec:
      serviceAccountName: <service-account-name> (3)
      mode: Resource
      resources:
      - apiVersion: v1
        kind: Event
      sink:
        ref:
          apiVersion: eventing.knative.dev/v1alpha1
          kind: KafkaSink
          name: <sink-name> (4)
    1 The name of the event source.
    2 The namespace of the event source.
    3 The service account for the event source.
    4 The Kafka sink name.