Upgrade Confluent for Kubernetes¶

Before you start the upgrade process, make sure your Kubernetes cluster is among the Supported Environments for the target version of Confluent for Kubernetes (CFK).

We recommend that you perform this upgrade separate from making other changes to your clusters, such as scaling up, changing configuration, or rotating credentials.

Upgrade CFK¶

Review Upgrade considerations and address any required steps.
If you are upgrading your CFK 2.x to 3.x to deploy and manage Confluent Platform 7.x, set the annotation for the components you want to use Log4j:
```
kubectl annotate <CR kind> <CR name> \
    platform.confluent.io/use-log4j1=true \
     --namespace <namespace>
```
The platform.confluent.io/use-log4j1=true annotation is required to use Confluent Platform 7.x with CFK 3.0+.

Disable resource reconciliation.

To prevent Confluent Platform components from rolling restarts, temporarily disable resource reconciliation of the components in each namespace where you have deployed Confluent Platform, specifying the CR kinds and CR names:

kubectl annotate connect connect \
    platform.confluent.io/block-reconcile=true \
     --namespace <namespace>

kubectl annotate controlcenter controlcenter \
     platform.confluent.io/block-reconcile=true \
     --namespace <namespace>

kubectl annotate kafkarestproxy kafkarestproxy \
     platform.confluent.io/block-reconcile=true \
     --namespace <namespace>

kubectl annotate kafka kafka \
     platform.confluent.io/block-reconcile=true \
     --namespace <namespace>

kubectl annotate ksqldb ksqldb \
     platform.confluent.io/block-reconcile=true \
     --namespace <namespace>

kubectl annotate schemaregistry schemaregistry \
     platform.confluent.io/block-reconcile=true \
     --namespace <namespace>

For ZooKeeper-based Confluent Platform 7.9 or earlier versions:

kubectl annotate zookeeper zookeeper \
     platform.confluent.io/block-reconcile=true \
     --namespace <namespace>

Add the CFK Helm repo:

helm repo add confluentinc https://packages.confluent.io/helm

helm repo update

Get the CFK chart.
- From the Helm repo:
  - To get the latest CFK chart:
```
helm pull confluentinc/confluent-for-kubernetes --untar
```
  - To get a specific version of the CFK chart, get the image tag of the CFK version from Confluent for Kubernetes image tags, and specify the version tag with the --version flag:
```
helm pull confluentinc/confluent-for-kubernetes --version <CFK image tag> --untar
```
- From a download bundle as specified in Deploy CFK using the download bundle.

IMPORTANT. Upgrade Confluent Platform custom resource definitions (CRDs).

This step is required because Helm does not support upgrading or deleting CRDs using Helm. For more information, see the Helm documentation.

kubectl apply -f confluent-for-kubernetes/crds/

If the above kubectl apply command returns an error similar to the below:

The CustomResourceDefinition "kafkas.platform.confluent.io" is invalid:
metadata.annotations: Too long: must have at most 262144 bytes make: ***
[install-crds] Error 1

Run the following commands:

kubectl apply --server-side=true -f <CRD>

If running kubectl apply with the --server-side=true flag returns an error similar to the below:

Apply failed with 1 conflict: conflict with "helm" using
apiextensions.k8s.io/v1: .spec.versions Please review the fields
above--they currently have other managers.

Run kubectl apply with an additional flag, --force-conflicts:

kubectl apply --server-side=true --force-conflicts -f <CRD>

Upgrade CFK to 3.0.0.
- If you deployed customized CFK using the values file, run the following command to upgrade CFK:
```
helm upgrade --install confluent-operator \
  confluentinc/confluent-for-kubernetes \
  --values <path-to-values-file> \
  --namespace <namespace>
```
- If you deployed CFK without customizing the values file, run the following command to upgrade CFK:
```
helm upgrade --install confluent-operator \
  confluentinc/confluent-for-kubernetes \
  --namespace <namespace>
```
- If you deployed CFK from a download bundle, upgrade CFK as specified in Deploy CFK using the download bundle.
Alternatively, upgrade CFK to a specific version, such as a hotfix or a patch version.
- If you deployed CFK using the values file, in your values.yaml, update the CFK image.tag to the image tag of the CFK version specified in Confluent for Kubernetes image tags:
```
image:
  tag: "<CFK image tag>"
```
  And run the following command to upgrade CFK:
```
helm upgrade --install confluent-operator \
  confluentinc/confluent-for-kubernetes \
  --values <path-to-values-file> \
  --namespace <namespace>
```
- If you did not use a customized values.yaml for CFK deployment, run the following command to upgrade CFK to a specific version, using the image tag of the CFK version specified in Confluent for Kubernetes image tags:
```
helm upgrade --install confluent-operator \
  confluentinc/confluent-for-kubernetes \
  --version <CFK image tag>
  --namespace <namespace>
```

Enable resource reconciliation for each Confluent Platform components that you disabled reconciliation in the first step above:

kubectl annotate <component CR kind> <cluster name> \
  platform.confluent.io/block-reconcile- \
  --namespace <namespace>

Upgrade the CFK init container.

Upgrade CFK init container¶

In each Confluent Platform component CR, update the CFK init container image tag to the version of CFK you are upgrading to, 3.0.0:

kind: <Confluent component>
spec:
  image:
    init: confluentinc/confluent-init-container:3.0.0