kubebuilder_v3_migration.md

Kubebuilder V3 Migration

Druid Operator project has started the move from operator SDK to Kubebuilder v2 framework.
In order to finish the project migration and to avoid the upgrade of Kubebuilder v3 in different time, the project combines both in the following version.

There are now more components that are being deployed:

• permissions for controller leader election
• metrics
• proxy sidecar to the controller

These components are part of the standard Kubebuilder deployment and are being added in order to stand with the best practices of Kubernetes and Kubebuilder.

This guide will help you go through the migration to Kubebuilder V3.
Note: These guides assumes that the current operator is running in the druid-operator namespace.

For Helm Managed Druid

Current Helm deployment is missing a labelSelector + podSpec label value: control-plane: controller-manager. These fields cannot be updated in place on existing Deployment.
This section helps you to first add these fields to the Deployment and then will guide you through the upgrade stage.

1. Get Druid Operator's deployment object

kubectl get deployments.apps -n druid-operator druid-operator -o yaml > druid-deployment-temp.yaml

2. Make the following changes:

• Add new label to labelSelector and to labels
• Change the deployment name to druid-operator-temp
• Remove the kubectl.kubernetes.io/last-applied-configuration annotation

apiVersion: apps/v1
kind: Deployment
metadata:
  ...
  name: druid-operator-temp # Name change
spec:
  ...
  selector:
    matchLabels:
      app.kubernetes.io/instance: druid-operator
      app.kubernetes.io/name: druid-operator
      control-plane: controller-manager # New label
  template:
    metadata:
      creationTimestamp: null
      labels:
        app.kubernetes.io/instance: druid-operator
        app.kubernetes.io/name: druid-operator
        control-plane: controller-manager # New label
    ...

3. Apply a second deployment

kubectl apply -f druid-deployment-temp

4. Delete original deployment

kubectl delete deployment -n druid-operator druid-operator

5. Edit druid-deployment-temp.yaml deployment's name back to original name:

apiVersion: apps/v1
kind: Deployment
metadata:
  ...
  name: druid-operator # Back to original name
spec:
  ...
  selector:
    matchLabels:
      app.kubernetes.io/instance: druid-operator
      app.kubernetes.io/name: druid-operator
      control-plane: controller-manager # New label
  template:
    metadata:
      creationTimestamp: null
      labels:
        app.kubernetes.io/instance: druid-operator
        app.kubernetes.io/name: druid-operator
        control-plane: controller-manager # New label
    ...

6. Apply the updated original deployment

kubectl apply -f druid-deployment-temp

7. Delete temp deployment

kubectl delete deployment -n druid-operator druid-operator-temp

NOTE: You should now have the original deployment with the new labelSelector and you are ready for moving into new deployment 8. Apply the new helm chart with the same name and same namespace.

For YAMLs Managed Druid

Kubebuilder is responsible for generating the deployment YAMLs. By default, the generated namespace is druid-operator-system. The new deployment name of the operator is also changed to: druid-operator-controller-manager.
Either way, you should look at the deployment YAMLs before you are deploying them. Service account, role and role binding that will replace the current ones - all should be in the same name.

There are two ways you can choose to deploy the new YAMLs:

In Kubebuilder default namespace

1. Apply the new controller in the druid-operator-system namespace.
   NOTE: Make sure this is a different namespace that the existing operator

# Set the tag you want for the controller
cd config/manager
kustomize edit set image controller=datainfrahq/druid-operator:${IMG_TAG}
# Back to root and apply
cd ../../
kustomize build config/default | kubectl apply -f -

2. Remove the old namespace.

kubectl delete ns druid-operator

In the current namespace

1. Edit Kustomize YAMLs

# Set the namespace you want for the controller
cd config/default
kustomize edit set namespace druid-operator
cd ../../
# Set the tag you want for the controller
cd config/manager
kustomize edit set image controller=datainfrahq/druid-operator:${IMG_TAG}
cd ../../

2. Apply the YAMLs

kustomize build config/default | kubectl apply -f -

3. Delete the old deployment

kubectl delete deployment -n druid-operator druid-operator