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Helm

⚙ Introducing Helm: Sailing Smoothly Through Kubernetes Deployments 🚀

Are you diving into the world of Kubernetes deployments and feeling a bit lost at sea? Don't worry, Helm is here to rescue you! Let's sail through Helm and make your Kubernetes journey smoother.

🤔 What is Helm?

Helm is a package manager for Kubernetes applications, designed to simplify the process of deploying, managing, and scaling containerized applications. Think of it as your go-to tool for streamlining the management of complex Kubernetes resources.

🏗️ Helm Structure:

The Helm structure consists of:

  1. Charts: Bundles of pre-configured Kubernetes resources that define the structure of an application.
  2. Templates: Dynamic YAML files within charts, allowing parameterization and customization.
  3. Values: Configuration options that can be customized during deployment.
  4. Charts Repository: A centralized location for sharing and discovering Helm charts.

🧩 Components in a Helm Chart:

When you crack open a Helm chart, you'll find several key components:

my-chart/
├── charts/
├── templates/
│ ├── NOTES.txt
│ ├── deployment.yaml
│ ├── service.yaml
│ └── ... (other k8s manifest files)
├── Chart.yaml
├── values.yaml
└── README.md
  1. Chart.yaml: Metadata about the chart, including name, version, and dependencies.
  2. Templates: Kubernetes manifest files with placeholders for dynamic values.
  3. Values.yaml: Default configuration values for the chart.
  4. Charts: Subcharts or dependencies required by the main chart.
  5. README.md: Documentation providing instructions and guidance on using the chart.
  6. NOTES.txt: Helpful information and post-installation notes for users.

⚙️ Helm Basic Commands:

Getting started with Helm is a breeze thanks to its intuitive command-line interface. Here are some essential commands:

  • helm create <chart_name>: Create a new chart.
  • helm install <release_name> <chart_name>: Install a chart.
  • helm upgrade <release_name> <chart_name>: Upgrade a deployed release.
  • helm list: List deployed releases.
  • helm uninstall <release_name>: Uninstall a release.

🚀 Sample Helm Project Files:

Now, let's dive into a sample Helm project to see how these concepts come together:

templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ .Values.deploymentname }}  # 🚀 Name of the Deployment
spec:
  replicas: 1  # 🚶 Number of desired replicas
  selector:
    matchLabels:
      app: {{ .Values.appname }}  # 🏷️ Selector to match pods with the label "app: wavecafe"
  template:
    metadata:
      labels:
        app: {{ .Values.appname }}  # 🏷️ Labels applied to pods created by this template
    spec:
      containers:
        - name: my-app-container  # 📦 Name of the container
          image: "{{ .Values.image.name }}:{{ .Values.image.tag }}"  # 🐳 Docker image to use
          ports:
            - name: cafe-port  # 🌐 Name of the port
              containerPort: 80  # 🚪 Port that the container listens on
templates/service.yaml
apiVersion: v1
kind: Service
metadata:
  name: wave-cafe  # ☕ Name of the Service
spec:
  selector:
    app: {{ .Values.appname }}  # 🏷️ Select pods with the label "app: wavecafe"
  ports:
    - protocol: TCP  # 🌐 Protocol for the port
      port: 80  # 🚪 Port on the Service
      targetPort: cafe-port  # 🚀 Port on the pods to forward traffic to
  type: LoadBalancer
Chart.yaml
apiVersion: v2
name: wavecafe
description: A Helm chart for Kubernetes

type: application

version: 0.1.0

appVersion: "1.16.0"
values.yaml
appname: wavecafe
deploymentname: wavecafe
servicename: wave-cafe

image:
  name: saitejairrinki/wavecafe
  tag: v1
Additional Features

In this Helm repository, I have added Horizontal Pod Autoscaling (HPA) and Kubernetes probes to ensure high availability and improved reliability.

Step-by-Step Guide:

  1. Create a Chart: Start by creating a Helm chart named wavecafe using the command: 

    helm create wavecafe

  2. Delete Templates: Next, delete all the files in the templates folder created by Helm: 

    rm wavecafe/templates/*

  3. Update YAML Files: Update the deployment.yaml and service.yaml files with the above provided content in templates folder. wrt values.yaml file.

  4. Install the Chart: Deploy your application using Helm with the following command: 

    helm install my-release wavecafe/ --values wavecafe/values.yaml

  5. Upgrade (Optional): Make changes to your application and upgrade the release: 

    helm upgrade my-release wavecafe/ --values wavecafe/values.yaml

  6. Uninstall: When you're done, uninstall the release: 

    helm uninstall my-release

Wrapping Up:

With Helm as your guiding star, Kubernetes deployments become smoother and more manageable than ever before. Bon voyage on your Kubernetes journey!

Happy Helming! ⚓🌟