Configuring Helm Charts with Raw YAML Data in KOTS

Packaging an application
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When building applications with KOTS and Helm, you may need to allow users to provide raw YAML configuration data such as arbitrary key-value pairs for labels, annotations, or environment variables. This article demonstrates how to use the textarea config type in KOTS to achieve this functionality.

Basic Implementation

Step 1: Define the Config Schema

Use the textarea type in your KOTS config to accept raw YAML input:

apiVersion: kots.io/v1beta1
kind: Config
metadata:
  name: my-app-config
spec:
  groups:
  - name: extra_config
    title: Extra Configuration
    description: Extra settings
    items:
    - name: podAnnotations
      title: Pod Annotations
      type: textarea

Step 2: Reference Config in HelmChart Resource

Pass the configuration to your Helm chart using template functions:

apiVersion: kots.io/v1beta2
kind: HelmChart
metadata:
  name: my-chart
spec:
  chart:
    name: my-chart
    chartVersion: 0.1.0
  values:
    podAnnotations: repl{{ ConfigOption "podAnnotations" | nindent 8 }}

Step 3: Use Values in Helm Templates

In your Helm template, consume the values with proper YAML handling:

  template:
    metadata:
      {{- with .Values.podAnnotations }}
      annotations:
        {{- toYaml . | nindent 8 }}
      {{- end }}

Base64 Encoding for Safety

For complex configurations or when indentation safety is a concern, you can require users to provide base64-encoded values:

HelmChart with Base64 Decoding

apiVersion: kots.io/v1beta2
kind: HelmChart
metadata:
  name: my-chart
spec:
  chart:
    name: my-chart
    chartVersion: 0.1.0
  values:
    complexConfig: repl{{ ConfigOption "complexConfig" | Base64Decode | nindent 8 }}

Additional Resources

For passing arbitrary Helm values, see: How can I add the ability to provide arbitrary Helm values using the KOTS config?

For more other configuration patterns and examples, check out the platform-examples repository which demonstrates different configuration scenarios and best practices.