🐳 Running Reddit Clone using Helm Charts inside Kubernetes Cluster☸️

Introduction

In this blog post, we will walk you through the Helm in K8s. We will learn how we can package our Kubernetes resources and how we can deploy the application using K8's package manager Helm.

💼 What is Helm in K8's?

Helm is a package manager for Kubernetes applications. It simplifies the process of defining, installing, and upgrading even the most complex Kubernetes applications. Essentially,
Helm allows you to define your Kubernetes applications as charts.
A Helm chart is a collection of pre-configured Kubernetes resources, which can be versioned, shared, and deployed as a single unit.
Helm provides templating, allowing you to parameterize your Kubernetes manifests and create dynamic, reusable configurations.

🤔 Why We Need Helm?

Helm solves several challenges in the Kubernetes deployment process:

Simplified Deployment: Helm packages Kubernetes manifests into a single unit, making it easier to manage and deploy complex applications.
Versioning and Rollbacks: Helm enables versioning of your applications, allowing you to roll back to previous versions if new deployments cause issues.
Templating: Helm's templating engine enables the dynamic generation of Kubernetes manifests, making it easy to customize deployments for different environments or use cases.
Collaboration: Helm charts can be shared via Helm repositories, making collaboration among developers and promoting the sharing of best practices.

🧩 Helm Components

Here are the components of the Helm.

Chart: A Helm package that contains pre-configured Kubernetes resources.
Values.yaml: A file where users can define customizable parameters for their charts.
Templates: Kubernetes manifest files with Helm-specific templating.
Release: A deployed instance of a Helm chart.
Repository: A collection of pre-packaged charts that users can fetch from.

🏛 Helm Architecture

As we we know we are interacting with our K8's cluster with the help of Kubectl CLI which communicates with the Kube API server and proceeds with the rest of the things.
Now to work with helm command, Helm internally communicates with Kubectl CLI so that the helm chart can understand which Kubernetes cluster it is interacting with

📌 Real-World Example

Imagine you are managing a microservices-based application with multiple services that need to be deployed and scaled independently. Helm allows you to create charts for each service, define their dependencies, and manage their deployments as a cohesive application. When you need to update a service or roll back to a previous version due to issues, Helm simplifies the process, making your DevOps tasks more efficient and error-free.

Helm is a valuable tool in the DevOps toolbox, streamlining Kubernetes deployments and making it easier to manage complex applications in a containerized environment.

🛠️ Helm Installation

📜 Prerequisites

Kubernetes cluster: You should have a Kubernetes cluster up and running.

To install Helm use the below command in your system.

      curl https://baltocdn.com/helm/signing.asc | gpg --dearmor | sudo tee /usr/share/keyrings/helm.gpg > /dev/null
      sudo apt-get install apt-transport-https --yes
      echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/helm.gpg] https://baltocdn.com/helm/stable/debian/ all main" | sudo tee /etc/apt/sources.list.d/helm-stable-debian.list
      sudo apt-get update
      sudo apt-get install helm
      helm version

📄 Basic helm command

Create helm chart:

Create the helm chart directory with some predefined YAML files and folders like Chart.yaml, values.yaml, templates folder, deployment.yaml, ingress.yaml, service.yaml, serviceaccount.yaml etc.
```
  #helm-chart-name can be anything as per your convenient
  helm create <helm-chart-name>
```
Install helm chart:

Note: The helm install command takes two arguments -
1. First argument - Release name that you pick.
2. Second argument - Chart you want to install(typically directory you created using helm create command).
```
 helm create <release-name> <chart-name>
```
Helm chart list

List of all installed helm charts.
```
  helm list -a
```
Helm chart directory structure:

Use to view helm chart directory structure after creating helm chart.
```
  tree <actual-chartname>
```
Helm Upgrade:

If you made any changes in the helm chart you need to upgrade your helm chart to reflect the changes.
```
  helm upgrade <release-name> <chart-name>
```
Helm Rollback:

If you want to switch to your previous version of the helm chart you need to use the helm rollback command.

Note: To rollback you need to specify the revision number of the helm chart.
```
  helm rollback <release-name> <revision-number>
```
Helm debug and dry-run:

Use it to validate your helm chart before installation.
```
  helm install <release-name> --debug --dry-run <chart-name>
```

Helm template:

Renders the chart templates locally which means it validates the helm chart templates.

  #actual-helchart-name is the name of your chart 
  #which is created after hitting the helm create command
  helm templete <actual-helchart-name>

Helm Lint:

Use it to find any errors or misconfigurations with the helm chart.

  #actual-helchart-name is the name of your chart 
  #which is created after hitting the helm create command 
  helm lint <actual-helchart-name>

Helm uninstall:

Use to uninstall/remove the helm chart.
```
  helm uninstall <helchart-name>
```
To know more about the helm command visit the official helm site.

https://helm.sh/docs/intro/cheatsheet/