Deploy Java Application to Tomcat using Jenkins and Docker

🎯 Project Objective

• Build a Java WAR application using Jenkins

• Containerize Tomcat with Docker

• Deploy the WAR file into Tomcat container automatically using Jenkins

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🧰 Tools Used

• Amazon EC2 (Amazon Linux 2)

• GitHub (Java WAR project)

• Jenkins

• Docker

• Apache Tomcat (Dockerized)

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🚀 Step-by-Step Procedure

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1️⃣ Launch EC2 Instance with Amazon Linux 2

Security Group Ports:

• 22 (SSH)

• 8080 (Tomcat)

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2️⃣ Install Required Packages

sudo yum update -y
sudo yum install java-1.8.0-openjdk git -y

Install Jenkins & Docker:
(Use your Day 1 Jenkins setup)

sudo yum install docker -y
sudo service docker start
sudo usermod -aG docker ec2-user

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3️⃣ Clone a Sample Java Project

Use a sample Maven project that builds a .war file
(e.g., https://github.com/spring-projects/spring-petclinic)

git clone https://github.com/spring-projects/spring-petclinic.git

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4️⃣ Dockerfile for Tomcat Deployment

Create a Dockerfile:

FROM tomcat:9-jdk8

COPY target/*.war /usr/local/tomcat/webapps/app.war

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5️⃣ Jenkins Pipeline Script

pipeline {
    agent any

    tools {
        maven 'Maven3'
    }

    stages {
        stage('Checkout') {
            steps {
                git 'https://github.com/spring-projects/spring-petclinic.git'
            }
        }

        stage('Build WAR') {
            steps {
                sh 'mvn clean package'
            }
        }

        stage('Build Docker Image') {
            steps {
                sh 'docker build -t petclinic-tomcat .'
            }
        }

        stage('Run Docker Container') {
            steps {
                sh 'docker run -d -p 8080:8080 --name tomcat-app petclinic-tomcat'
            }
        }
    }
}

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6️⃣ Access the App

• Visit http://<your-ec2-ip>:8080/app

• The Java WAR is deployed into the Tomcat container automatically via Jenkins

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✅ Expected Outcome

• WAR file is built via Jenkins

• Docker image is created with embedded Tomcat + WAR

• App runs inside a Docker container and is accessible via port 8080