Chart structure
- Docker & Kubernetes course
- Advanced
- Lesson 8/70
- 4 min
Learn the Helm chart directory structure.
Chart structure
A chart is a specific folder layout. helm create produces a sample skeleton:
magaza/
Chart.yaml # name, version, description
values.yaml # default values
templates/ # YAMLs with Go templates
deployment.yaml
service.yaml
_helpers.tpl # shared template pieces
NOTES.txt # post-install message
charts/ # dependent charts# Chart.yaml
apiVersion: v2
name: magaza
version: 0.1.0 # chart version
appVersion: "1.4.2" # application versionTemplates
The files under templates/ use the Go template language. {{ .Values.x }} reads from values.yaml, {{ .Release.Name }} from the release name, {{ .Chart.AppVersion }} from Chart.yaml:
apiVersion: apps/v1
kind: Deployment
metadata:
name: {{ .Release.Name }}-web
spec:
replicas: {{ .Values.replicaCount }}
template:
spec:
containers:
- name: web
image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"Practice A chart skeleton
Two steps: write the command creating a chart skeleton named magaza; then write the Chart.yaml contents: apiVersion: v2, name: magaza, version: 0.1.0, appVersion: "1.4.2".
Starter code
# buraya yazSample solution
helm create magaza
# Chart.yaml
apiVersion: v2
name: magaza
version: 0.1.0
appVersion: "1.4.2"Expected output
Creating magaza
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 What is the difference between version and appVersion in Chart.yaml?
- appVersion is the Kubernetes version
- version is the Helm version
- version is the chart package's version, appVersion the application inside it Correct answer
- They are the same
Explanation: When the templates change, version goes up; when the image changes, appVersion.
2 Read the value from values.yaml.
Question
replicas: {{ .____.replicaCount }}
Answer
replicas: {{ .Values.replicaCount }}Explanation: .Values is values.yaml and --set values.
3 Match.
| Term | Meaning |
|---|---|
Chart.yaml |
Chart information |
values.yaml |
Default values |
templates/ |
Templated YAML |
.Release.Name |
Release name |