Global configuration - Administer | Serverless | Red Hat OpenShift Service on AWS

Configuring the default channel implementation

The OpenShift Serverless Operator manages the global configuration of a Knative installation, including propagating values from the KnativeServing and KnativeEventing custom resources to system config maps. Any updates to config maps which are applied manually are overwritten by the Operator. However, modifying the Knative custom resources allows you to set values for these config maps.

Knative has multiple config maps that are named with the prefix config-. All Knative config maps are created in the same namespace as the custom resource that they apply to. For example, if the KnativeServing custom resource is created in the knative-serving namespace, all Knative Serving config maps are also created in this namespace.

The spec.config in the Knative custom resources have one <name> entry for each config map, named config-<name>, with a value which is be used for the config map data.

Configuring the default channel implementation

Prerequisites

You have administrator permissions on Red Hat OpenShift Service on AWS.
You have installed the OpenShift Serverless Operator and Knative Eventing on your cluster.
If you want to use Kafka channels 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/v1alpha1
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.

Additional resources