Add-on Development Guide

Harvester add-ons allow you to enable and disable specific Harvester and third-party components based on your requirements. Add-ons function as a wrapper for the RKE2 HelmChart resource definition (CRD).

Prerequisites

• An existing Harvester cluster

Add-on Specifications

The Addon CRD supports the following fields:

apiVersion: harvesterhci.io/v1beta1
kind: Addon                         
metadata:
  name: example-add-on           # Name of add-on
  namespace: example-namespace  # Namespace where the add-on CRD is deployed and where the associated Kubernetes components will be deployed
  labels:                       # Optional add-on labels
    Add-on.harvesterhci.io/experimental: "true" # Predefined label used on the Harvester UI to identify add-ons with the "experimental" maturity level
spec:
  enabled: false                # Boolean indicating if an add-on should be enabled or disabled on definition
  repo: https://chartsrepo.com  # Helm chart repository containing the Helm chart managed by the add-on
  version: "v0.19.0"            # Version of the Helm chart to be installed
  chart: mychart                # Name of the Helm chart in the Helm chart repository
  valuesContent: |-             # File (values.yaml) that must be passed to the Helm chart
    contents of values.yaml
    that need to be passed
    to the chart

note

Experimental add-ons are not directly packaged in Harvester. An example is the rancher-vcluster add-on.

Installation

kubectl apply -f /path/to/add-on.yaml

Usage

After creating an Addon CRD, you can can toggle the enabled field to enable and disable the associated Helm chart.

Upgrade

Changes to the repo, version, chart or valueContent fields will trigger a helm upgrade, which forces an upgrade of the existing Helm chart.

Uninstallation

kubectl delete -f /path/to/Add-on.yaml