What is HELM | Why We need HELM | Create HELM Chart ?

Table of Contents

What is HELM ?

Helm is a packaging manager for Kubernetes applications. It is used in repeated installation of Kubernetes applications and services. Helm can do the following

Create a chart from scratch
Package the charts
Interact with the repositories
Install and uninstall charts into the Kubernetes cluster
Manage release cycle of charts installed with Helm

It is graduated project in the CNCF(Cloud Native Computing Foundation) and maintained by the community group.

Chart, Repository and Release are the three concepts of Helm

Why we need HELM ?

When deploying an application on Kubernetes, it is required to define and manage several Kubernetes resources such as pods, services, deployments, and replica-sets. Each of these require to write a group of manifest files in YAML format. In the context of a complex application deployment it becomes a difficult task to maintain several manifest files for each of these resources.

Furthermore, templating the manifest files and providing configuration parameters externally, can become crucial which will allow to customize the deployments. Dependency management and version control are some other important factors to consider as well.

This is where Helm plays a vital role in automating the process of installing, configuring and upgrading complex Kubernetes applications. Helm simplifies this process and creates a single package that can be advertised to your cluster.

What is HELM Chart ?

A chart is a collection of YAML files that describe a set of Kubernetes resources.

Helm charts helps to define, install and upgrade the most complex Kubernetes applications.

Charts are easy to create, version, share and publish

The charts can be shared by adding to the repositories (public or private)

The charts stored in the repositories can be used by anyone and modified instead of creating a new chart from scratch

Helm Charts are simply Kubernetes YAML manifests combined into a single package that can be advertised to your Kubernetes clusters. Helm packages are called charts

Once packaged, installing a Helm Chart into your cluster is as easy as running a single helm install, which really simplifies deployment of containerized applications

Charts can be searched in Artifact hub where community group post number of charts or helm hub

Advantages of HELM charts

Manage complexity
Easy to share
Easy to upgrade
Roll back

How to Install HELM ?

Helm can be installed in different ways either from binary version or from the script

To install from Binary, you can use Helm official site to latest version of helm

1. Download the desired version

2. Unpack the folder

3. Move to the desired destination usr/local/bin/helm

To install from script

Run the following commands to download and change the permission

curl -fsSL -o get_helm.sh https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3
chmod 700 get_helm.sh
./get_helm.sh

What is HELM | Why We need HELM | Create HELM Chart ? 1

Create your First HELM Chart

Open your terminal to create helm charts for your service

helm create hello-world

You should see the output on your terminal as below,
Creating new-chart

Navigate to newly created directory

cd helm-world

This creates a simple charts for your service

With ls command, you can see the contents of the new-chart folder

Chart.yaml charts templates values.yaml

Structure of HELM Chart

To view tree structure of your helm charts run below command

tree hello-world

Output:

hello-world
├── charts
├── Chart.yaml
├── templates
│  ├── deployment.yaml
│  ├── _helpers.tpl
│  ├── hpa.yaml
│  ├── ingress.yaml
│  ├── NOTES.txt
│  ├── serviceaccount.yaml
│  ├── service.yaml
│  └── tests
│      └── test-connection.yaml
└── values.yaml

Basic HELM commands

helm search – to search for Helm charts
helm search hub : searches in the Artifact Hub
helm search repo : searches in the repository
helm install – to install a chart
helm install [release name] [name of the chart]
helm status – to check the status
helm upgrade – to upgrade the changes
helm rollback – to rollback
helm uninstall to uninstall helm
helm list – to check all the currently installed releases

Conclusion: