Helm Chart Deployment Guide for Spring Boot and PostgreSQL

Preliminary Setup

Install Docker Desktop and Enable Kubernetes

Download and install Docker Desktop from Docker's official website.
Open Docker Desktop and navigate to Settings > Kubernetes.
Check the box for Enable Kubernetes and click on Apply & Restart.

Install Java 21 Using SDKMAN

Install SDKMAN by running the following command:
```
curl -s "https://get.sdkman.io" | bash
```
Open a new terminal window and install Java 21:
```
sdk install java 21.0.0
```

Use Gradle to Build the Project

Navigate to your Spring Boot project directory.
Run the following command to build the project using Gradle:
```
./gradlew build
```

This will generate a JAR file in the build/libs/ directory.

Run Docker Compose Locally

Make sure you have a docker-compose.yaml file at the root of your project.
Run the following command to bring up the services:
```
docker-compose up --build
```
Open a browser and navigate to http://localhost:8080/hello to ensure that the application is running as expected.

Build Docker Image

Run the following command to build a Docker image for your Spring Boot application:

docker build -t helloworld-spring-boot-app:latest .

Helm Chart Directory Structure

Your Helm chart directory should look like this:

my-helm-chart/
├── templates/
│   ├── deployment.yaml
│   ├── postgres-service.yaml
│   └── springboot-loadbalancer-service.yaml
├── values.yaml
└── Chart.yaml

templates/: Your Kubernetes YAML definitions.
values.yaml: Configuration variables for your templates.
Chart.yaml: Metadata about the Helm chart.

Creating Basic Helm Chart Files

Chart.yaml: This file should contain meta-information about the Helm chart.
```
apiVersion: v2
name: my-helm-chart
version: 0.1.0
```
values.yaml: This file should hold configurable parameters that will be fed into your templates. See example values for Spring Boot and PostgreSQL configurations.
deployment.yaml: This file should contain the Deployment configuration for your Spring Boot application, including any environment variables it might need.
postgres-service.yaml: This file should define a Kubernetes Service for your PostgreSQL database, as well as a Deployment to manage the database Pods.

Deploy Helm Chart

Once your Helm chart is ready, you can deploy it to your Kubernetes cluster:

Lint the chart to catch issues:
```
helm lint ./my-helm-chart
```
Package the chart:
```
helm package ./my-helm-chart
```

Deploy the chart:

helm install my-helm-release ./my-helm-chart

That's it! You now have a Helm chart for deploying a Spring Boot application and PostgreSQL database, complete with a LoadBalancer and health checks.

rokon12 / k8-demo