Upgrading using the Knative Operator

The attribute spec.version is the only field you need to change in the Serving or Eventing custom resource to perform an upgrade. You do not need to specify the version for the patch number, because the Knative Operator matches the latest available patch number, as long as you specify major.minor for the version. For example, you only need to specify "0.22" to upgrade to the 0.22 release, you do not need to specify the exact patch number.

The Knative Operator supports up to the last three major releases. For example, if the current version of the Operator is 0.22, it bundles and supports the installation of Knative versions 0.19, 0.20, 0.21 and 0.22.

NOTE: In the following examples, Knative Serving custom resources are installed in the knative-serving namespace, and Knative Eventing custom resources are installed in the knative-eventing namespace.

Performing the upgrade

To upgrade, apply the Operator custom resources, adding the spec.version for the Knative version that you want to upgrade to:

  1. kubectl apply -f - <<EOF
  2. apiVersion: operator.knative.dev/v1alpha1
  3. kind: KnativeServing
  4. metadata:
  5.   name: knative-serving
  6.   namespace: knative-serving
  7. spec:
  8.   version: "0.22"
  9. EOF

Verifying the upgrade

To confirm that your Knative components have successfully upgraded, view the status of their pods in the relevant namespaces. All pods will restart during the upgrade and their age will reset. If you upgraded Knative Serving and Eventing, enter the following commands to get information about the pods for each namespace:

  1. kubectl get pods --namespace knative-serving
  1. kubectl get pods --namespace knative-eventing

These commands return something similar to:

  1. NAME                                                     READY   STATUS      RESTARTS   AGE
  2. activator-6875896748-gdjgs                               1/1     Running     0          58s
  3. autoscaler-6bbc885cfd-vkrgg                              1/1     Running     0          57s
  4. autoscaler-hpa-5cdd7c6b69-hxzv4                          1/1     Running     0          55s
  5. controller-64dd4bd56-wzb2k                               1/1     Running     0          57s
  6. istio-webhook-75cc84fbd4-dkcgt                           1/1     Running     0          50s
  7. networking-istio-6dcbd4b5f4-mxm8q                        1/1     Running     0          51s
  8. storage-version-migration-serving-serving-0.20.0-82hjt   0/1     Completed   0          50s
  9. webhook-75f5d4845d-zkrdt                                 1/1     Running     0          56s
  1. NAME                                              READY   STATUS      RESTARTS   AGE
  2. eventing-controller-6bc59c9fd7-6svbm              1/1     Running     0          38s
  3. eventing-webhook-85cd479f87-4dwxh                 1/1     Running     0          38s
  4. imc-controller-97c4fd87c-t9mnm                    1/1     Running     0          33s
  5. imc-dispatcher-c6db95ffd-ln4mc                    1/1     Running     0          33s
  6. mt-broker-controller-5f87fbd5d9-m69cd             1/1     Running     0          32s
  7. mt-broker-filter-5b9c64cbd5-d27p4                 1/1     Running     0          32s
  8. mt-broker-ingress-55c66fdfdf-gn56g                1/1     Running     0          32s
  9. storage-version-migration-eventing-0.20.0-fvgqf   0/1     Completed   0          31s
  10. sugar-controller-684d5cfdbb-67vsv                 1/1     Running     0          31s

You can also verify the status of Knative by checking the custom resources:

  1. kubectl get KnativeServing knative-serving --namespace knative-serving
  1. kubectl get KnativeEventing knative-eventing --namespace knative-eventing

These commands return something similar to:

  1. NAME              VERSION         READY   REASON
  2. knative-serving   0.20.0          True
  1. NAME               VERSION        READY   REASON
  2. knative-eventing   0.20.0         True

Rollback

If the upgrade fails, you can rollback to restore your Knative to the previous version. For example, if something goes wrong with an upgrade to 0.22, and your previous version is 0.21, you can apply the following custom resources to restore Knative Serving and Eventing to version 0.21.

For Knative Serving:

  1. kubectl apply -f - <<EOF
  2. apiVersion: operator.knative.dev/v1alpha1
  3. kind: KnativeServing
  4. metadata:
  5.   name: knative-serving
  6.   namespace: knative-serving
  7. spec:
  8.   version: "0.21"
  9. EOF

For Knative Eventing:

  1. kubectl apply -f - <<EOF
  2. apiVersion: operator.knative.dev/v1alpha1
  3. kind: KnativeEventing
  4. metadata:
  5.   name: knative-eventing
  6.   namespace: knative-eventing
  7. spec:
  8.   version: "0.21"
  9. EOF