Using Helm to Package and Deploy your Application

Business Scenario

Using different manifests, you manually deployed your application with all corresponding Kubernetes objects to a Kubernetes cluster. Now you want to use Helm to package your deployment manifest and deploy it via Helm to your cluster.

Live Environment

In this exercise, you will create, customize, and deploy a Helm chart for a Deployment.

Prerequisites

You have successfully created a SAP BTP, Kyma runtime instance in the SAP BTP subaccount.
You have configured kubectl to work with your SAP BTP, Kyma runtime instance.
Furthermore, you have installed the Helm CLI on your local machine.

Once you have the Helm CLI installed, you can create a Helm chart for your deployment. The Helm CLI provides a command to create a Helm chart for you. This will create a few sample files for you to get started with. However, in this approach, we will create the Helm chart manually from scratch.

Task 1: Create, customize and deploy a Helm chart for a deployment

Steps

Create a new directory for your Helm chart. Call it hello-kyma-chart and change into it.

Create a new file called Chart.yaml and specify information about the chart, such as the name, version, description, and so on. Add the following content to the file:

Code Snippet

12345
apiVersion: v2
name: hello-kyma-chart
description: A Helm chart for the Hello Kyma example application
type: application # A chart can be either an 'application' or a 'library' chart.
version: 0.1.0 # This is the chart version.

Create a new file called values.yaml and specify the default configuration values like replicaCount and image.tag. Add the following content to the file:
Code Snippet
```
123
replicaCount: 1
image:
  tag: "1.0.0"
```
Create a new directory called templates and change into it.
In this directory, you can add all the templates for your Helm chart. For now, we will only add a template for the Deployment.

Create a new file called deployment.yaml and specify the Kubernetes Deployment's definition and use your configuration values. Add the following content to the file:

Code Snippet

123456789101112131415161718192021222324
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ .Release.Name }}
spec:
  replicas: {{ .Values.replicaCount }} 
  selector:
    matchLabels:
      app: {{ .Release.Name }}
  template:
    metadata: 
      labels: 
        app: {{ .Release.Name }}
    spec:
      containers: 
        - name: hello-kyma
          image: ghcr.io/sap-samples/kyma-runtime-learning-journey/hello-kyma:{{ .Values.image.tag }}
          ports:
            - containerPort: 8080 
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%

Hint

Take advantage of the {{ .Release.Name }} and {{ .Values.replicaCount }} placeholders to make use of the configuration values that you specified in the values.yaml file. The {{ Release.Name }} placeholder will be replaced with the name of the Helm release. The {{ .Chart.AppVersion }} placeholder will be replaced with the version of the application that you specified in the Chart.yaml file.

To perform a dry-run of your Helm chart to see if it is valid, run the following command inside the hello-kyma-chart directory:
Code Snippet
```
1
helm template hello-kyma .
```
You should now see a rendered output of your Helm chart.
Install the Helm chart in your cluster.
1. Run the following command inside the hello-kyma-chart directory:
  Code Snippet
```
1
helm install hello-kyma-helm .
```
  You should now see the following output:
  Code Snippet
```
123456
NAME: hello-kyma-helm
LAST DEPLOYED: Tue Jun 8 11:25:00 2021
NAMESPACE: default
STATUS: deployed
REVISION: 1
TEST SUITE: None
```
2. To see the Deployment in your cluster, run the following command:
  Code Snippet
```
1
kubectl get deployments
```
  You should now see the following output:
  Code Snippet
```
12
NAME     READY   UP-TO-DATE   AVAILABLE   AGE
hello-kyma-helm     1/1     1           1           2m
```
Update the values.yaml file and change the replicaCount to 2.
Update the Helm chart in your cluster.
1. Run the following command inside the hello-kyma-chart directory:
  Code Snippet
```
1
helm upgrade hello-kyma-helm .
```
  You should now see the following output:
  Code Snippet
```
1234567
Release "hello-kyma-helm" has been upgraded. Happy Helming!
NAME: hello-kyma-helm
LAST DEPLOYED: Tue Jun 8 11:25:00 2021
NAMESPACE: default
STATUS: deployed
REVISION: 2
TEST SUITE: None
```
2. List the Deployments using kubectl:
  Code Snippet
```
1
kubectl get deployments
```
  You should now see the following output:
  Code Snippet
```
12
NAME   READY   UP-TO-DATE   AVAILABLE   AGE
hello-kyma-helm   2/2     2           2            4m
```
View the Helm release in Kyma dashboard.
1. Open Kyma dashboard in your browser.
2. Go to Apps → Helm Releases and choose the hello-kyma-helm release.
  You should now see the following output:
  Note
  Once you discover other Kubernetes objects later in this course, you will be able, for example, to extend your helm chart with other manifests for services, ingresses, and more.

Result

You have successfully created a Helm chart for your deployment and deployed it to your cluster.