Deploy using Helm charts

Category : Kubernetes | Sub Category : Kubernetes With Java | By Prasad Bonam Last updated: 2023-11-21 13:34:39 Viewed : 625

Deploying using Helm charts involves creating a Helm chart, which is a package of pre-configured Kubernetes resources, and then installing the chart onto a Kubernetes cluster. Below is a step-by-step guide to deploying a simple NGINX application using Helm charts:

1. Install Helm:

If you have not already, you need to install Helm on your local machine. Follow the instructions on the official Helm installation guide for your operating system.

2. Create a Helm Chart:

Create a new directory for your Helm chart. In this example, let`s call it my-nginx-chart.

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mkdir my-nginx-chart
cd my-nginx-chart

Inside the directory, create a Chart.yaml file with the following content:

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apiVersion: v2
name: my-nginx-chart
description: A Helm chart for deploying NGINX
version: 0.1.0

3. Create values.yaml:

Create a values.yaml file with default configuration values:

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# values.yaml
replicaCount: 3
image:
  repository: nginx
  tag: latest
  pullPolicy: IfNotPresent
service:
  type: LoadBalancer
  port: 80

4. Create Templates:

Create a templates/ directory and add two files: deployment.yaml and service.yaml.

deployment.yaml:

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# templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "my-nginx-chart.fullname" . }}
spec:
  replicas: {{ .Values.replicaCount }}
  selector:
    matchLabels:
      app: {{ include "my-nginx-chart.name" . }}
      release: {{ .Release.Name }}
  template:
    metadata:
      labels:
        app: {{ include "my-nginx-chart.name" . }}
        release: {{ .Release.Name }}
    spec:
      containers:
      - name: nginx
        image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
        imagePullPolicy: {{ .Values.image.pullPolicy }}
        ports:
        - containerPort: 80

service.yaml:

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# templates/service.yaml
apiVersion: v1
kind: Service
metadata:
  name: {{ include "my-nginx-chart.fullname" . }}
spec:
  selector:
    app: {{ include "my-nginx-chart.name" . }}
    release: {{ .Release.Name }}
  ports:
    - protocol: TCP
      port: {{ .Values.service.port }}
      targetPort: 80
  type: {{ .Values.service.type }}

5. Install the Helm Chart:

Now, you can install the Helm chart onto your Kubernetes cluster:

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helm install my-nginx-release ./my-nginx-chart

Replace my-nginx-release with the desired release name.

6. Verify the Deployment:

Check the status of the deployment:

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kubectl get deployments

Check the status of the service:

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kubectl get services

If you are using Minikube, you can access the NGINX service using:

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minikube service my-nginx-release

For cloud providers, wait for the external IP to be assigned to the service and access the application using that IP.

7. Upgrade the Helm Chart:

To make changes to your deployment, update the values.yaml file or the template files, and then upgrade the Helm chart:

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helm upgrade my-nginx-release ./my-nginx-chart

8. Cleanup:

To delete the deployed Helm release and associated resources:

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helm uninstall my-nginx-release

This removes the NGINX deployment and service from the cluster.

Helm charts provide a convenient way to package, deploy, and manage applications on Kubernetes, making it easier to share and reproduce complex application configurations.