Helm Charts: the package manager for Kubernetes¶

• It is a tool that simplifies Kubernetes application deployment by bundling its resources (like pods, services, deployments, configmaps, etc.) into a single package called a Helm Chart.
• It automates the process of defining, installing and upgrading Kubernetes applications.
• They are packages for Kubernetes that help you define, install, and manage Kubernetes applications.

But what is it?¶

A helm chart is a collection of files organised in a specific directory structure, which includes:

1. chart.yaml: Metadata about the chart (name, version,description)
2. values.yaml: defualt configuration values (can be overridden)
3. templates/ : Kubernetes manifest templates (in YAML) that Helm renders using values from values.yaml
4. NOTES.txt: optional, provides user instructions after installing the chart

Helm Chart Structure¶

myapp/
├── Chart.yaml
├── values.yaml
├── templates/
│   ├── deployment.yaml
│   ├── service.yaml
│   └── ingress.yaml
└── NOTES.txt

Why use this?¶

• Simpilifies complex Kubernetes deployments
• Supports versioning and rollbacks
• Enables reuse and sharing of charts
• Manages configurations cleanly with values.yaml

How it Works¶

1. Create a Chart: Define Kubernetes resources using templates.
2. Install the Chart:

helm install my-release ./myapp

• Helm takes the templates, substitutes values, and deploys the resources to Kubernetes.

• Upgrade: Modify values.yaml or templates and upgrade using:

helm upgrade my-release ./myapp

1. Rollback: If the upgrade fails:

helm rollback my-release

1. Uninstall: To remove an application:

helm uninstall my-release

Example: deployment template¶

apiVersion: apps/v1
kind: Deployment
metadata:
  name: { { .Release.Name } }
spec:
  replicas: { { .Values.replicaCount } }
  template:
    spec:
      containers:
        - name: my-container
          image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"

Example: values.yaml¶

replicaCount: 2
image:
  repository: nginx
  tag: latest

{
  "Kubernetes-counter": 10
}