Deploying a Spring Boot Application with Docker

In the dynamic world of software development, deploying applications efficiently is a crucial aspect. Docker has emerged as a game-changer, providing a containerization solution that ensures consistent and reproducible deployments. This article will guide you through the process of deploying a Spring Boot application using Docker, combining the power of Spring Boot's simplicity with Docker's containerization benefits.

Setting the Stage: Prerequisites

Before we dive into deploying our Spring Boot application with Docker, let's ensure you have the necessary tools installed:

1. Java Development Kit (JDK): Make sure you have the JDK installed on your system.

2. Spring Boot: Develop your Spring Boot application.

3. Docker: Install Docker on your machine. You can download it from the official Docker website.

Creating a Spring Boot Application:

Assuming you have a Spring Boot application ready, if not, you can quickly generate one using Spring Initializr.

$ curl https://start.spring.io/starter.zip -o my-spring-boot-app.zip
$ unzip my-spring-boot-app.zip -d my-spring-boot-app
$ cd my-spring-boot-app

Dockerizing the Spring Boot Application:

Now, let's Dockerize our Spring Boot application by creating a Dockerfile in the project root.

# Dockerfile
FROM openjdk:11-jre-slim
COPY target/my-spring-boot-app.jar /app.jar
CMD ["java", "-jar", "/app.jar"]

This Dockerfile uses the official OpenJDK 11 image, copies the JAR file into the container, and sets the command to run the Spring Boot application.

Building the Docker Image:

Navigate to the project directory and build the Docker image.

$ docker build -t my-spring-boot-app .

Running the Docker Container:

Now that we have the Docker image, let's run it in a container.

$ docker run -p 8080:8080 my-spring-boot-app

Your Spring Boot application is now running in a Docker container, accessible at http://localhost:8080.

Additional Docker Commands:

• List running containers:

  $ docker ps
  

• View container logs:

  $ docker logs <container-id>
  

• Stop a running container:

  $ docker stop <container-id>
  

Deploying on Docker Compose:

Docker Compose simplifies the orchestration of multi-container Docker applications. Create a docker-compose.yml file:

version: '3'
services:
  my-spring-boot-app:
    image: my-spring-boot-app
    ports:
      - "8080:8080"

Run your application with:

$ docker-compose up

Congratulations! You've successfully deployed a Spring Boot application with Docker. Containerization provides a consistent and portable environment, making your application deployment hassle-free. Experiment with different Docker features to optimize your development workflow further.