capi-custom-extension is a runtime extension of Cluster API (CAPI) that implements the logic for the BeforeClusterUpgradeHook. This extension provides additional functionality for handling cluster upgrades before the actual upgrade process takes place.

Before using this extension, ensure that you have the following prerequisites in place:

• A ClusterUpgrade resource must be created. Here's an example of a ClusterUpgrade resource manifest:

  apiVersion: cluster.aruba.it/v1alpha1
  kind: ClusterUpgrade
  metadata:
    name: clusterupgrade-sample-v1.21.2-v1.22.0
    namespace: default
  spec:
    nodes_ip:
    - 10.244.0.12

• The ClusterUpgrade resource should be in the desired state with relevant annotations, labels, and status conditions based on your use case.

To test the extension, run the following command:

kubectl create --raw '/api/v1/namespaces/default/services/https:sample-service:443/proxy/hooks.runtime.cluster.x-k8s.io/v1alpha1/beforeclusterupgrade/before-cluster-upgrade' -f <(echo '{"apiVersion":"hooks.runtime.cluster.x-k8s.io/v1alpha1","kind":"BeforeClusterUpgradeRequest","cluster":{"metadata":{"namespace":"default","name":"clusterupgrade-sample"}},"fromKubernetesVersion":"v1.21.2","toKubernetesVersion":"v1.22.0"}')

This command creates a BeforeClusterUpgradeRequest for the specified cluster and triggers the extension logic.

To build the project, execute the following commands:

docker build --platform=linux/amd64 -t YOUR_DOCKER_IMAGE_NAME --build-arg builder_image=golang:1.19.3 .

Replace YOUR_DOCKER_IMAGE_NAME with the desired name for your Docker image. This command builds the project and creates the Docker image.

To push the Docker image to a repository, use the following command:

docker push YOUR_DOCKER_IMAGE_NAME

Replace YOUR_DOCKER_IMAGE_NAME with the actual name of your Docker image. This command pushes the image to the specified repository.

To deploy the extension to your cluster, run the following command:

kubectl -k apply -k config/default

This command applies the Kubernetes manifests located in the config/default directory to deploy the extension. Make sure to modify the extension_image_patch.yaml file in the config/default directory to update the image reference accordingly.

Note: Replace YOUR_DOCKER_IMAGE_NAME with the actual name of your Docker image in the extension_image_patch.yaml file.