Helm for beginer - Deploy nginx to Google Kubernetes Engine

#kubernetes #beginners #nginx #gke

Introduction

Helm is a package manager for Kubernetes, which simplifies the process of deploying and managing applications on Kubernetes clusters. Helm uses a packaging format called charts, which are collections of files that describe a related set of Kubernetes resources.

Key Components of Helm

Charts: Helm packages are called charts. A chart is a collection of files that describe a related set of Kubernetes resources. A single chart might be used to deploy something simple, like a memcached pod, or something complex, like a full web app stack with HTTP servers, databases, caches, and so on.
Values: Charts can be customized with values, which are configuration settings that specify how the chart should be installed on the cluster. These values can be set in a values.yaml file or passed on the command line.
Releases: When you install a chart, a new release is created. This means that one chart can be installed multiple times into the same cluster, and each can be independently managed and upgraded.

Prerequisites

To get started, you'll need to:

Have some knowledge about Kubernetes. You can check out this article for basic information.
A Google Account with the necessary permissions to use Kubernetes.
Installed gcloud and kubectl

Practical Steps

First, use gcloud to create a cluster like this:

gcloud container clusters create {cluster name} \
  --project {project id} \
  --zone {zone id} \
  --machine-type {machine type id} \
  --num-nodes {number of node}

# ex:
gcloud container clusters create k8s-cluster \
  --project project-id \
  --zone asia-southeast1-a \
  --machine-type e2-micro \
  --num-nodes 1

To install helm, use the following command:

curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash

To create a helm chart, use the following command:

helm create chart-name

After executing, a template is created that includes files like development.yaml, service.yaml, and others, similar to working with Kubernetes. Among these files, pay special attention to values.yaml. The values in this file are bound to the template when Helm is installed. By simply changing these values according to your needs, you can easily modify the deployment configuration.

Next, in the values.yaml file, look for the following information:

image:
  repository: nginx

service:
  type: ClusterIP
  port: 80

The repository is a Docker image used for deployment, which you can customize as needed.
The current service type is ClusterIP, using port 80.

Here, you can change the service type to LoadBalancer. Then, install helm chart as follows:

The change to a LoadBalancer service type allows your cloud provider to supply an EXTERNAL-IP. You can then retrieve the EXTERNAL-IP information as follows:

If you keep the original content of the values.yaml file, you can install helm chart and change the service type to LoadBalancer like this: