World K4: Notes, Lockers & Packages

Write a small chart

You will learn: what is inside a Helm chart, and how values fill its templates.

Checked with Kubernetes 1.37 on 31 Oct 2026

The problem

You are here: cluster kind-dev namespace default

~ $ helm template ./kedai---# Source: kedai/templates/service.yamlapiVersion: v1kind: Servicemetadata:  labels:    app.kubernetes.io/instance: release-name    app.kubernetes.io/managed-by: Helm    app.kubernetes.io/name: kedai    app.kubernetes.io/version: 1.0.0    helm.sh/chart: kedai-0.1.0  name: release-name-kedaispec:  ports:  - name: http    port: 80    protocol: TCP    targetPort: http  selector:    app.kubernetes.io/instance: release-name    app.kubernetes.io/name: kedai  type: ClusterIP---# Source: kedai/templates/deployment.yamlapiVersion: apps/v1kind: Deploymentmetadata:  labels:    app.kubernetes.io/instance: release-name    app.kubernetes.io/managed-by: Helm    app.kubernetes.io/name: kedai    app.kubernetes.io/version: 1.0.0    helm.sh/chart: kedai-0.1.0  name: release-name-kedaispec:  replicas: 2  selector:    matchLabels:      app.kubernetes.io/instance: release-name      app.kubernetes.io/name: kedai  template:    metadata:      labels:        app.kubernetes.io/instance: release-name        app.kubernetes.io/managed-by: Helm        app.kubernetes.io/name: kedai        app.kubernetes.io/version: 1.0.0        helm.sh/chart: kedai-0.1.0    spec:      containers:      - image: nginx:1.29-alpine        imagePullPolicy: IfNotPresent        name: kedai        ports:        - containerPort: 80          name: http          protocol: TCP

Your team copies shop.yaml for every new stall. Only the name, the image and the tray count change. Write the YAML once, with holes.

Watch

Drag a card into a box. Or tap the card, then tap the box.

A chart is a folder in three parts. Chart.yaml is the label. values.yaml holds the defaults. templates/ holds YAML with holes.

Watch

A piece of templates/deployment.yaml. Tap every line with a hole.

0 of 3 found

Each {{ }} is a hole. Helm fills .Values holes from : values.yaml, or your --set.

Try it

Fill the image hole with 1.30-alpine. Look at the image line.

You are here: cluster kind-dev namespace default

dev-control-planeOpenManager

No trays here.

dev-workerOpen

No trays here.

dev-worker2Open

No trays here.

Time: +0s (sped up)

Hint

A dot walks into the values: image.tag is tag inside image.

Predict

values.yaml says replicaCount: 2. You add --set replicaCount=4. What does the YAML say?

Check

Good chart habit or not? Swipe each one.

Swipe right for good, left for needs work. Or use the buttons.

1 / 4

Put the image tag in values.yaml, not in the template.

Check

You run helm template pasar ./kedai. What is the Deployment called?

You did it!

You can now read a small chart and fill it with values.

Go deeper (optional)

helm create kedai makes a starter chart like this one. helm lint ./kedai finds mistakes. helm package ./kedai makes a .tgz to share. Templates use Go templates, so {{ .Values.name | quote }} wraps a value in quotes. Chart.yaml starts with apiVersion: v2.

Real rep (optional), on your own machine with Helm 4:

Real mission

Make a starter chart.
helm create kedai
Open kedai/values.yaml and find replicaCount.
Check it.
helm lint ./kedai
Fill it with your own order.
helm template shop ./kedai --set replicaCount=3
Tidy up.
rm -r kedai

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