Bootstrapping and samples

Creating a New Operator Project

Using the Maven Plugin

The simplest way to start a new operator project is using the provided Maven plugin, which generates a complete project skeleton:

mvn io.javaoperatorsdk:bootstrapper:[version]:create \
  -DprojectGroupId=org.acme \
  -DprojectArtifactId=getting-started

This command creates a new Maven project with:

• A basic operator implementation
• Maven configuration with required dependencies
• Generated CustomResourceDefinition (CRD)

Building Your Project

Build the generated project with Maven:

mvn clean install

The build process automatically generates the CustomResourceDefinition YAML file that you’ll need to apply to your Kubernetes cluster.

Exploring Sample Operators

The sample-operators directory contains real-world examples demonstrating different JOSDK features and patterns:

Available Samples

webpage

• Purpose: Creates NGINX webservers from Custom Resources containing HTML code
• Key Features: Multiple implementation approaches using both low-level APIs and higher-level abstractions
• Good for: Understanding basic operator concepts and API usage patterns

mysql-schema

• Purpose: Manages database schemas in MySQL instances
• Key Features: Demonstrates managing non-Kubernetes resources (external systems)
• Good for: Learning how to integrate with external services and manage state outside Kubernetes

tomcat

• Purpose: Manages Tomcat instances and web applications
• Key Features: Multiple controllers managing related custom resources
• Good for: Understanding complex operators with multiple resource types and relationships

Running the Samples

Prerequisites

The easiest way to try samples is using a local Kubernetes cluster:

• minikube
• kind
• Docker Desktop with Kubernetes

Step-by-Step Instructions

1. Apply the CustomResourceDefinition:

   kubectl apply -f target/classes/META-INF/fabric8/[resource-name]-v1.yml
   

2. Run the operator:

   mvn exec:java -Dexec.mainClass="your.main.ClassName"
   

   Or run your main class directly from your IDE.

3. Create custom resources: The operator will automatically detect and reconcile custom resources when you create them:

   kubectl apply -f examples/sample-resource.yaml
   

Detailed Examples

For comprehensive setup instructions and examples, see:

• MySQL Schema sample README
• Individual sample directories for specific setup requirements

Next Steps

After exploring the samples:

1. Review the patterns and best practices guide
2. Learn about implementing reconcilers
3. Explore dependent resources and workflows for advanced use cases