Default channel implementation - Channels | Eventing | Red Hat OpenShift Serverless 1.34

You can use the default-ch-webhook config map to specify the default channel implementation of Knative Eventing. You can specify the default channel implementation for the entire cluster or for one or more namespaces. Currently the InMemoryChannel and KafkaChannel channel types are supported.

Configuring the default channel implementation

Prerequisites

You have administrator permissions on OpenShift Container Platform.
You have installed the OpenShift Serverless Operator and Knative Eventing on your cluster.
If you want to use Knative channels for Apache Kafka as the default channel implementation, you must also install the KnativeKafka CR on your cluster.

Procedure

Modify the KnativeEventing custom resource to add configuration details for the default-ch-webhook config map:

apiVersion: operator.knative.dev/v1beta1
kind: KnativeEventing
metadata:
  name: knative-eventing
  namespace: knative-eventing
spec:
  config: (1)
    default-ch-webhook: (2)
      default-ch-config: |
        clusterDefault: (3)
          apiVersion: messaging.knative.dev/v1
          kind: InMemoryChannel
          spec:
            delivery:
              backoffDelay: PT0.5S
              backoffPolicy: exponential
              retry: 5
        namespaceDefaults: (4)
          my-namespace:
            apiVersion: messaging.knative.dev/v1beta1
            kind: KafkaChannel
            spec:
              numPartitions: 1
              replicationFactor: 1

1	In `spec.config`, you can specify the config maps that you want to add modified configurations for.
2	The `default-ch-webhook` config map can be used to specify the default channel implementation for the cluster or for one or more namespaces.
3	The cluster-wide default channel type configuration. In this example, the default channel implementation for the cluster is `InMemoryChannel`.
4	The namespace-scoped default channel type configuration. In this example, the default channel implementation for the `my-namespace` namespace is `KafkaChannel`.

Configuring a namespace-specific default overrides any cluster-wide settings.