Skip to content

Latest commit

 

History

History
75 lines (50 loc) · 3.13 KB

REVIEW_GUIDELINES.md

File metadata and controls

75 lines (50 loc) · 3.13 KB

Chart Review Guidelines

Anyone is welcome to review pull requests. Besides our technical requirements and best practices, here's an overview of review guidelines.

Immutability

Chart releases must be immutable. Any change to a chart warrants a chart version bump even if it is only changes to the documentation.

Chart Metadata

The Chart.yaml should be as complete as possible. The following fields are mandatory:

  • name (same as chart's directory)
  • home
  • version
  • appVersion
  • description
  • maintainers (name should be Github username)

Dependencies

Stable charts should not depend on charts in incubator.

Names and Labels

Resources and labels should follow some conventions. The standard resource metadata should be this:

name: {{ template "myapp.fullname" . }}
labels:
  app: {{ template "myapp.name" . }}
  chart: {{ .Chart.Name }}-{{ .Chart.Version | replace "+" "_" }}
  release: {{ .Release.Name }}
  heritage: {{ .Release.Service }}

Note that templates have to be namespaced. With Helm 2.7+, helm create does this out-of-the-box. The app label should use the name template, not fullname as is still the case with older charts.

Label selectors for services must have both app and release labels.

selector:
  app: {{ template "myapp.name" . }}
  release: {{ .Release.Name }}

If a chart has multiple components, a component label should be added (e. g. component: server). The resource name should get the component as suffix (e. g. name: {{ template "myapp.fullname" . }}-server). The component label must be added to label selectors as well.

Formatting

  • Yaml file should be indented with two spaces.
  • List indentation style should be consistent.
  • There should be a single space after {{ and before }}.

Configuration

  • Docker images should be configurable. Image tags should use stable versions.
image:
  name: myapp
  tag: 1.2.3
  pullPolicy: IfNotPresent
  • The use of the default function should be avoided if possible in favor of defaults in values.yaml.
  • It is usually best to not specify defaults for resources and to just provide sensible values that are commented out as a recommendation, especially when resources are rather high. This makes it easier to test charts on small clusters or Minikube. Setting resources should generally be a conscious choice of the user.

Documentation

README.md and NOTES.txt are mandatory. README.md should contain a table listing all configuration options. NOTES.txt should provide accurate and useful information how the chart can be used/accessed.

Compatibility

We officially support compatibility with the current and the previous minor version of Kubernetes. Generated resources should use the latest possible API versions compatible with these versions. For extended backwards compatibility conditional logic based on capalilities may be used (see built-in objects).