Configuring the Eventing Operator Custom Resource

The Knative Eventing operator can be configured with these options:

NOTE: Kubernetes spec level policies cannot be configured using the Knative operators.

Version Configuration

Cluster administrators can install a specific version of Knative Eventing by using the spec.version field. For example, if you want to install Knative Eventing 0.16.0, you can apply the following KnativeEventing custom resource:

apiVersion: operator.knative.dev/v1alpha1
kind: KnativeEventing
metadata:
  name: knative-eventing
  namespace: knative-eventing
spec:
  version: 0.16.0

If spec.version is not specified, the Knative Operator will install the latest available version of Knative Eventing. If users specify an invalid or unavailable version, the Knative Operator will do nothing. The Knative Operator always includes the latest 3 minor release versions. For example, if the current version of the Knative Operator is 0.16.x, the earliest version of Knative Eventing available through the Operator is 0.14.0.

If Knative Eventing is already managed by the Operator, updating the spec.version field in the KnativeEventing resource enables upgrading or downgrading the Knative Eventing version, without needing to change the Operator.

Note that the Knative Operator only permits upgrades or downgrades by one minor release version at a time. For example, if the current Knative Eventing deployment is version 0.14.x, you must upgrade to 0.15.x before upgrading to 0.16.x.

Eventing Configuration by ConfigMap

The Knative Eventing operator CR is configured the same way as the Knative Serving operator CR. Because the operator manages the Knative Eventing installation, it will overwrite any updates to the ConfigMaps which are used to configure Knative Eventing. The KnativeEventing custom resource allows you to set values for these ConfigMaps via the operator. Knative Eventing has multiple ConfigMaps named with the prefix config-. The spec.config in KnativeEventing has one entry <name> for each ConfigMap named config-<name>, with a value which will be used for the ConfigMap’s data.

For example, if you would like to change your default channel from InMemoryChannel into KafkaChannel, here is what your Eventing CR looks like, to modify the ConfigMap config-br-default-channel:

apiVersion: operator.knative.dev/v1alpha1
kind: KnativeEventing
metadata:
  name: knative-eventing
  namespace: knative-eventing
spec:
  config:
    br-default-channel:
      channelTemplateSpec: |
        apiVersion: messaging.knative.dev/v1beta1
        kind: KafkaChannel
        spec:
          numPartitions: 10
          replicationFactor: 1

All the ConfigMaps are created in the same namespace as the operator CR. You can use the operator CR as the unique entry point to edit all of them.

Private repository and private secrets

The Knative Eventing operator CR is configured the same way as the Knative Serving operator CR. For more information, see the documentation on “Private repository and private secret” in Serving operator for detailed instruction.

Knative Eventing also specifies only one container within one Deployment resource. However, the container does not use the same name as its parent Deployment, which means the container name in Knative Eventing is not the unique identifier as in Knative Serving. Here is the list of containers within each Deployment resource:

Component Deployment name Container name
Core eventing eventing-controller eventing-controller
Core eventing eventing-webhook eventing-webhook
Eventing Broker broker-controller eventing-controller
In-Memory Channel imc-controller controller
In-Memory Channel imc-dispatcher dispatcher

The default field can still be used to replace the images in a predefined format. However, if the container name is not a unique identifier, e.g. eventing-controller, you need to use the override field to replace it, by specifying deployment/container as the unique key.

Some images are defined via environment variable in Knative Eventing. They can be replaced by taking advantage of the override field. As Knative does not have a consistent way to specify container images, we have a known issue here.

Download images in predefined format without secrets:

This example shows how you can define custom image links that can be defined in the CR using the simplified format docker.io/knative-images/${NAME}:{CUSTOM-TAG}.

In the example below:

  • the custom tag v0.13.0 is used for all images
  • all image links are accessible without using secrets
  • images are defined in the accepted format docker.io/knative-images/${NAME}:{CUSTOM-TAG}

First, you need to make sure your images are pushed to the following image tags:

Deployment Container Docker image
eventing-controller eventing-controller docker.io/knative-images/eventing-controller:v0.13.0
eventing-webhook docker.io/knative-images/eventing-webhook:v0.13.0
broker-controller eventing-controller docker.io/knative-images/broker-eventing-controller:v0.13.0
controller docker.io/knative-images/controller:v0.13.0
dispatcher docker.io/knative-images/dispatcher:v0.13.0

Then, you need to define your operator CR with following content:

apiVersion: operator.knative.dev/v1alpha1
kind: KnativeEventing
metadata:
  name: knative-eventing
  namespace: knative-eventing
spec:
  registry:
    default: docker.io/knative-images/${NAME}:v0.13.0
    override:
      broker-controller/eventing-controller: docker.io/knative-images-repo1/broker-eventing-controller:v0.13.0

As indicated, you replace {CUSTOM-TAG} with the custom tag v0.13.0. ${NAME} maps to the container name in each Deployment resource. The field default is used to define the image format for all containers, except the container eventing-controller in the deployment broker-controller. To replace the image for this container, you need to take advatage of the override field to specify individually, by using broker-controller/eventing-controller as the key`.

Download images from different repositories without secrets:

If your custom image links are not defined in a uniform format by default, you will need to individually include each link in the CR.

For example, to define the list of images:

Deployment Container Docker Image
eventing-controller eventing-controller docker.io/knative-images/eventing-controller:v0.13.0
eventing-webhook docker.io/knative-images/eventing-webhook:v0.13.0
controller docker.io/knative-images/controller:v0.13.0
dispatcher docker.io/knative-images/dispatcher:v0.13.0
broker-controller eventing-controller docker.io/knative-images/broker-eventing-controller:v0.13.0

The operator CR should be modified to include the full list:

apiVersion: operator.knative.dev/v1alpha1
kind: KnativeEventing
metadata:
  name: knative-eventing
  namespace: knative-eventing
spec:
  registry:
    override:
      eventing-controller/eventing-controller: docker.io/knative-images-repo1/eventing-controller:v0.13.0
      eventing-webhook/eventing-webhook: docker.io/knative-images-repo2/eventing-webhook:v0.13.0
      imc-controller/controller: docker.io/knative-images-repo3/imc-controller:v0.13.0
      imc-dispatcher/dispatcher: docker.io/knative-images-repo4/imc-dispatcher:v0.13.0
      broker-controller/eventing-controller: docker.io/knative-images-repo5/broker-eventing-controller:v0.13.0

If you would like to replace the image defined by environment variable, e.g. the envorinment variable DISPATCHER_IMAGE in the container controller of the deployment imc-controller, you need to adjust your CR into the following, if the target image is docker.io/knative-images-repo5/DISPATCHER_IMAGE:v0.13.0:

apiVersion: operator.knative.dev/v1alpha1
kind: KnativeEventing
metadata:
  name: knative-eventing
  namespace: knative-eventing
spec:
  registry:
    override:
      eventing-controller/eventing-controller: docker.io/knative-images-repo1/eventing-controller:v0.13.0
      eventing-webhook/eventing-webhook: docker.io/knative-images-repo2/eventing-webhook:v0.13.0
      imc-controller/controller: docker.io/knative-images-repo3/imc-controller:v0.13.0
      imc-dispatcher/dispatcher: docker.io/knative-images-repo4/imc-dispatcher:v0.13.0
      broker-controller/eventing-controller: docker.io/knative-images-repo5/broker-eventing-controller:v0.13.0
      DISPATCHER_IMAGE: docker.io/knative-images-repo5/DISPATCHER_IMAGE:v0.13.0

Download images with secrets:

If your image repository requires private secrets for access, you must append the imagePullSecrets attribute.

This example uses a secret named regcred. Refer to this guide to create your own private secrets. After you create the secret, edit your operator CR by appending the content below:

apiVersion: operator.knative.dev/v1alpha1
kind: KnativeEventing
metadata:
  name: knative-eventing
  namespace: knative-eventing
spec:
  registry:
    ...
    imagePullSecrets:
      - name: regcred

The field imagePullSecrets expects a list of secrets. You can add multiple secrets to access the images as below:

apiVersion: operator.knative.dev/v1alpha1
kind: KnativeEventing
metadata:
  name: knative-eventing
  namespace: knative-eventing
spec:
  registry:
    ...
    imagePullSecrets:
      - name: regcred
      - name: regcred-2
      ...

Configuring default broker class

Knative Eventing allows you to define a default broker class when the user does not specify one. The operator ships with two broker classes: ChannelBasedBroker and MTChannelBasedBroker. The field defaultBrokerClass indicates which class to use; if empty, the ChannelBasedBroker will be used. Here is an example specifying MTChannelBasedBroker as the default:

apiVersion: operator.knative.dev/v1alpha1
kind: KnativeEventing
metadata:
  name: knative-eventing
  namespace: knative-eventing
spec:
  defaultBrokerClass: MTChannelBasedBroker