Helm Chart Tutorial

Pre-requisites

One running Kubernetes cluster
Install kubectl

Install kubectl

curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
sudo install -o root -g root -m 0755 kubectl /usr/local/bin/kubectl
kubectl version --client

Install Helm

sudo apt-get install curl gpg apt-transport-https --yes
curl -fsSL https://packages.buildkite.com/helm-linux/helm-debian/gpgkey | gpg --dearmor | sudo tee /usr/share/keyrings/helm.gpg > /dev/null
echo "deb [signed-by=/usr/share/keyrings/helm.gpg] https://packages.buildkite.com/helm-linux/helm-debian/any/ any 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 CLI Commands

helm install <RELEASE_NAME> <CHART_NAME>
helm delete <RELEASE_NAME>
helm list -a
helm create helloworld

Helm Chart Directory Structure

tree helloworld

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

Edit `values.yaml`

# helloworld/values.yaml
service:
  type: NodePort
  port: 80

Install and List Helm Release

helm install myhelloworld helloworld
helm list -a
kubectl get service

Now browse ip:<port_no> in your browser to see the default nginx page.

Add Helm Chart Repository

helm repo add bitnami https://charts.bitnami.com/bitnami
helm search repo bitnami
helm repo list

Update Helm Chart Repository

helm repo update

Index Helm Chart Repository

The index command generates the index file for a directory containing packaged charts.

helm repo index helloworld
cat helloworld/index.yaml

Remove Helm Chart Repository

helm repo remove bitnami

Helm Upgrade

Upgrade a Helm chart after making changes. This will change the revision number.

helm upgrade myhelloworld helloworld

Helm Rollback

Rollback the Helm chart to a previous revision.

helm rollback myhelloworld 1

Key Benefits of Using Helmfile

Bundle several Helm Charts into a single Helmfile to manage your Kubernetes ecosystem.
Maintain isolation between different environments (development, staging, production).
Identify differences between new changes and existing deployments in your Kubernetes cluster.
Use Go Templates in Helmfile, with Sprig library functions like requiredEnv, exec, readFile, toYaml, fromYaml, setValueAtPath, get, tpl, required, fetchSecretValue, expandSecretRefs.
Deploy multi-tier applications inside your Kubernetes cluster with Helmfile.

Helmfile Installation and Usage Guide

Install Helmfile (Linux)

wget https://github.com/roboll/helmfile/releases/download/v0.144.0/helmfile_linux_amd64
mv helmfile_linux_amd64 helmfile
chmod 777 helmfile
sudo mv helmfile /usr/local/bin
helmfile -version

Create Your First Helmfile and Install a Helm Chart

Create a Helm chart:
```
helm create helloworld
```

Create a helmfile.yaml:

releases:
  - name: helloworldrelease   # release name
    chart: ./helloworld       # directory/chart name
    installed: true

Sync with Helmfile:
```
helmfile sync
helm list -a
```

Uninstall the Helm Chart Using Helmfile

Edit helmfile.yaml to set installed: false:

releases:
  - name: helloworldrelease
    chart: ./helloworld
    installed: false

Sync again:
```
helmfile sync
helm list -a
```

Use GitHub Repository for Installing Helm Chart with Helmfile

Edit helmfile.yaml:

repositories:
  - name: helloworld
    url: git+https://github.com/rahulwagh/helmchart@helloworld?ref=master&sparse=0

releases:
  - name: helloworldrelease
    chart: helloworld/helloworld
    installed: true

Sync:
```
helmfile sync
helm list -a
```

Deploy Multiple Helm Charts Using Helmfile

Create charts:

helm create helloworld1
helm create helloworld2