Integrating Tomcat/TomEE with Fabric8 for Seamless DevOps

In the world of DevOps, seamless integration is key. This is especially true when working with popular Java web servers like Tomcat and TomEE. Fabric8 is an excellent platform for enabling seamless DevOps, providing capabilities for continuous integration, deployment, and automation. In this guide, we'll discuss how to integrate Tomcat/TomEE with Fabric8 for a more streamlined DevOps workflow.

What is Fabric8?

Fabric8 is an open-source, microservices platform that provides essential capabilities for DevOps. It offers tools for Kubernetes and Red Hat OpenShift and facilitates continuous delivery, integration, and automation. Fabric8 aims to simplify the development, integration, deployment, and operation of microservices.

Why Integrate Tomcat/TomEE with Fabric8?

Integrating Tomcat or TomEE with Fabric8 offers several benefits for DevOps workflows. Fabric8 provides a simple and effective way to manage and automate the deployment of Java web applications. By leveraging Fabric8, developers and operations teams can easily create and promote container-based deployments. This integration also facilitates continuous delivery and streamlines the overall DevOps process.

Setting Up the Integration

To integrate Tomcat/TomEE with Fabric8, we'll need to follow these steps:

1. Build the Web Application: Create a simple Java web application, for example, a basic servlet, to deploy on Tomcat/TomEE.

2. Create a Docker Image: Dockerize the web application to prepare it for deployment as a container. This involves creating a Dockerfile that describes the container image and includes the necessary configurations.

3. Prepare Fabric8 Configuration: Configure Fabric8 to manage the deployment of the Dockerized web application. This involves specifying the Docker image details and deployment settings.

4. Deploy and Manage: Utilize Fabric8 to deploy and manage the web application on the chosen infrastructure, whether it's Kubernetes, Red Hat OpenShift, or another compatible platform.

By following these steps, we can seamlessly integrate Tomcat/TomEE with Fabric8, enabling efficient DevOps workflows.

Building the Web Application

Let's create a simple "Hello World" servlet using Java and Maven. Below is the code for the servlet class:

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class HelloWorldServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
        PrintWriter out = response.getWriter();
        out.println("Hello, World!");
    }
}

This simple servlet will serve as the example web application to deploy with Tomcat/TomEE and Fabric8.

Creating a Docker Image

To Dockerize our web application, we need to create a Dockerfile. The Dockerfile defines the image and its dependencies. Below is an example of a Dockerfile for our "Hello World" servlet:

# Use Tomcat as the base image
FROM tomcat:latest

# Copy the web application (WAR file) into the webapps directory of Tomcat
COPY HelloWorld.war /usr/local/tomcat/webapps/

In this Dockerfile, we use the official Tomcat image as the base image, and then copy our web application (in the form of a .war file) into the webapps directory of Tomcat. This sets up the image to deploy our web application.

Configuring Fabric8

Next, we need to configure Fabric8 to manage the deployment of our Dockerized web application. Fabric8 provides a simple and flexible way to define the deployment details. Below is a sample configuration file (deployment.yml) for Fabric8:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: hello-world
spec:
  replicas: 1
  selector:
    matchLabels:
      app: hello-world
  template:
    metadata:
      labels:
        app: hello-world
    spec:
      containers:
        - name: hello-world
          image: my-docker-registry/hello-world-servlet:latest
          ports:
            - containerPort: 8080

In this configuration file, we define a Kubernetes Deployment for our web application. We specify details such as the number of replicas, the container image to use, and the port to expose.

Deploy and Manage with Fabric8

With the web application Dockerized and the Fabric8 configuration in place, we can now use Fabric8 to deploy and manage the application. Fabric8 provides a streamlined interface for managing deployments, rolling updates, and scaling application instances.

By integrating Tomcat/TomEE with Fabric8, we have enabled a seamless DevOps workflow for deploying and managing Java web applications.

Closing the Chapter

Integrating Tomcat/TomEE with Fabric8 opens up a world of possibilities for DevOps workflows. It simplifies the deployment and management of Java web applications and facilitates continuous delivery and integration.

With this integration, developers and operations teams can focus on building great applications while leveraging the power of Fabric8 and containerization for efficient deployment and management.

In conclusion, integrating Tomcat/TomEE with Fabric8 is a significant step toward achieving a more seamless and efficient DevOps pipeline for Java web applications.