Smooth Sailing with Helm: A Beginner's Guide to Kubernetes Package Management

Contributed by : Chamod Perera

GitHub Repo : ?https://github.com/chamodshehanka/kcd-lahore-2024

Video Session : https://www.youtube.com/watch?v=kcz9Z6nRYL0

Welcome to “Smooth Sailing with Helm,” your beginner-friendly tutorial designed to steer through the complexities of Kubernetes application management. I'm Chamod Perera, a CNCF Ambassador and software engineer from the beautiful island of Sri Lanka, here to guide you through the world of Helm.

Introduction to Helm

Helm is the Kubernetes package manager, streamlining application deployment and management within Kubernetes clusters. It offers a utility akin to APT for Linux or Homebrew for macOS, tailored for Kubernetes environments.

Helm Installation

To start using Helm, install it on your system using the instructions tailored to your operating system:

# On macOS 
brew install helm 

# On Linux (with APT) 

sudo apt-get install helm 

# On Windows (with Chocolatey) choco install kubernetes-helm        

Helm as a Template Engine

Beyond package management, Helm excels as a template engine, simplifying the deployment of applications, especially useful for microservices architecture.

Creating a Helm Chart

Kick off by creating a Helm chart:

helm create kcdlahore-2024        

This command generates a new chart directory, kcdlahore-2024, equipped with the necessary files for a Helm chart.

Understanding Chart Structure

A Helm chart typically contains:

• Chart.yaml: Chart metadata
• values.yaml: Default configuration values
• templates/: Kubernetes resource templates
• charts/: Sub-charts, if any

Customizing Your Chart

Customize your chart by tweaking the values.yaml and the templates in the templates/ directory.

Deploying Nginx as an Example

Let’s apply what we've learned to deploy Nginx, demonstrating Helm's straightforward approach to managing Kubernetes applications.

Configuring Nginx in values.yaml

Adjust the values.yaml file to specify Nginx's image, tag, and other relevant configurations:

image:

  repository: nginx

  tag: latest

  pullPolicy: IfNotPresent

service:

  type: LoadBalancer

  port: 80         

Deploying with Helm

Deploy Nginx using your customized chart:

helm install kcdlahore-2024-release-1 ./kcdlahore-2024        

This command deploys Nginx to your Kubernetes cluster, utilizing the configurations defined in your chart.

Managing Deployments Across Environments

Helm's versatility shines when managing deployments across various environments, such as development, staging, and production.

Environment-specific Values Files

Create separate values files for different environments, like values-prod.yaml, and deploy using:

helm install kcdlahore-2024-release-1 ./kcdlahore-202 -f values-prod.yaml        

This approach allows for environment-specific configurations without altering the chart.

Advanced Helm Features

Helm also offers advanced features, such as hooks, to interact with the lifecycle of a release.

Leveraging Helm Hooks

For instance, to run a job before installation:

apiVersion: batch/v1
kind: Job
metadata:
  name: pre-install-hook
  namespace: {{ .Values.namespace }}
spec:
  template:
    spec:
      containers:
        - name: pre-install-hook
          image: alpine:latest
          command: ["echo", "Executing pre-installation hook"]
      restartPolicy: Never
  backoffLimit: 1        

It uses the Alpine Linux image to execute a simple command that echoes “Executing pre-installation hook.” The job runs once in the specified namespace, with no automatic retries upon failure, illustrating how Helm can perform tasks before installing the main application components.

Conclusion

Helm revolutionizes the Kubernetes deployment process, simplifying application management with its templating and packaging capabilities. By abstracting Kubernetes manifests into manageable templates, Helm empowers developers to focus more on development and less on deployment intricacies.

Begin your Helm journey today and streamline your Kubernetes application deployments for a smoother, more efficient workflow. Whether deploying a lightweight web server like Nginx or a complex application stack, Helm equips you with the tools needed for successful Kubernetes management.