Kubee Helmet Chart Dev

This page contains information for developer that wants to develop Kubee chart

Kind

CRDS

Charts that ends up with crds are CRDS charts. These charts are dedicated Helm Chart that follows the Helm CRD Method 2.

Cluster Chart

Cluster chart drives the provisioning of cluster. They use the templating capability of Helm to create a dynamic configuration based on the cluster configuration values file.

Library

A library chart is a chart that has common values and function. It is not meant to be installed. As of today, kubee has only one library chart, the kubee-cluster chart.

App

All other charts are app charts.

Annotations

You add the kubee-cluster chart as dependency to get the library in Chart.yaml

dependencies:
  - name: kubee-cluster
    version: 0.0.1
    repository: file://../cluster
    alias: cluster

You set in Chart.yaml the app name with the app.kubernetes.io/name annotation.

annotations:
  app.kubernetes.io/name: my-app-name

Then in the manifest:

• on metadata, you can use the kubee-manifest-labels function

metadata:
  labels:
    {{- include "kubee-manifest-labels" . | nindent 4 }}

• on select label the kubee-pod-labels function

selector:
  # example on service
  {{- include "kubee-pod-labels" . | nindent 2 }}
  # example on template for deployment/statefulset
  matchLabels:
    {{- include "kubee-pod-labels" . | nindent 6 }}

Chart Meta (Kind, Status, …)

Example:

annotations:
  chart.kubee/status: "stable"
  #  "stable" - can be installed
  #  "incubator" - been developed
  #  "deprecated" - no more maintained
  # A lead, the description in Chart.yaml is a short description
  chart.kubee/lead: "A big lead"
  chart.kubee/category: monitoring
  chart.kubee/kind: "crds"
    #  "app"  - apps
    #  "crds" - crds
  #  "cluster" - cluster driver
  #  "internal" - internal
  #  "library" - lib and shared values
  chart.kubee/engines: |
    - helm
    - jsonnet
    - kustomize

CRD Dependency Charts

You can define a CRD chart with the chart.kubee/crds annotations in the Chart.yaml.

Example:

• On a kubee crds chart

annotations:
  chart.kubee/crds: |
    - name: kubee-prometheus-crds
      version: 0.79.2
      repository: file://../prometheus-crds

• On a external crds chart

annotations:
  chart.kubee/crds: |
    - name: mariadb-operator/mariadb-operator-crds
      repository: https://helm.mariadb.com/mariadb-operator
      version: 0.37.1

FAQ: Why not multiple sub-chart by umbrella chart?

SubChart cannot by default be installed in another namespace than the umbrella chart. This is a known issue with helm and sub-charts

That’s why:

• the unit of execution is one sub-chart by umbrella chart
• kubee-cluster is a common sub-chart of all umbrella chart

Dev

Dev: Cross dependency

Cross Dependency are only used to share values.

When developing a Chart, you should:

• add them in Chart.yml and disable them with a condition

- name: kubee-traefik
  version: 0.0.1
  alias: traefik
  condition: kubee_internal.install_cross_dependency

• Install them locally

# with the installed version (f means force)
kubee helmet update-dependencies -f chart-name
# with the next version
./bin/kubee helmet update-dependencies -f chart-name
# or
task dep

Example: The chart kubee-dex depends on the kubee-oauth2-proxy that depends on the kubee-dex chart creating a recursion.

To avoid this recursion, we delete all dependency in the charts/dep/Chart.yaml file

Dev Command (tpl, dep, lint, …)

# Generate the template
task tpl
# Install the dependencies chart
task dep
task dep-force
# Generate the values.schema.json
task schema
# Generate the readme from README.md.gotmpl
task helm-docs

• Lint

helm lint .
# check the link
task docs-lint

FAQ

Why the CRDs are in the template directory and not in the CRDs directory

The crd are not in the crds directory because we want this manifests to be able to upgrade.

The home of Kubee Charts

Note

Helm Schema

We filter on the current chart because if we change a schema of a dependency, we need to regenerate all dependent schema, and it does not work for now.

helm schema --helm-docs-compatibility-mode -k additionalProperties --dependencies-filter kubee-mailpit

Why?

• because empty default value are seen as required and some dependent chart such as Traefik are out of control

To make it work, we need to create a script that make a custom call for each chart.

Support

Helm Schema: no schema found error

Just FYI. With the error:

If you'd like to use helm-schema on your chart dependencies as well, you have to build and unpack them before.
You'll avoid the "missing dependency" error message.

What they mean is when you have all your chart dependency in the charts/, you need to un-tar:

# go where your Chart.lock/yaml is located
cd <chart-name>

# build dependencies and un-tar them
helm dep build
ls charts/*.tgz |xargs -n1 tar -C charts/ -xzf

We tackle this problem with the helmet update-dependency command