Steps -

1. Create Ubuntu server -> T2 medium, 30 GB

2. Install Jenkins on ubuntu server. -

   https://www.jenkins.io/doc/book/installing/linux/

3. Install maven 3.8.7

   apt install maven -y

4. Nexus Installation on docker image

apt install docker.io -y

docker pull sonatype/nexus3

docker volume create nexus-data

docker run -d -p 8081:8081 --name nexus \

-v nexus-data:/nexus-data
sonatype/nexus3

5. Fetch password -

docker ps

docker exec -it nexus /bin/bash

cat /nexus-data/admin.password

da2a59b0-3c0d-4b8e-b309-fc5d3e0e7c0c

6. Install below Plugins on Jenkins server

7. Pipeline Maven Integration

8. Nexus Artifact Uploader

9. Navigate to Manage Jenkins -> Tools -> Configure Maven installation ->

   Name : M3 MAVEN_HOME : /usr/share/maven

10. Managed Jenkins -> Managed Files -> Add new config (Global-Setting)-> content -> 111

maven-releases admin admin123

<server>
  <id>maven-snapshots</id>
  <username>admin</username>
  <password>admin123</password>
</server>

9. Login to Jenkins servr

ls -l /var/lib/jenkins/.M2/

mkdir -p /var/lib/jenkins/.m2

vim /var/lib/jenkins/.m2/settings.xml

maven-releases admin admin123

<server>
  <id>maven-snapshots</id>
  <username>admin</username>
  <password>admin123</password>
</server>

10. Edit POM.xml for server IP

ex. 52.66.206.151

11. Write your Jenkinsfile

pipeline { agent any

environment {
    APP_NAME = "myapp"
}

stages {
    stage('Checkout Code') {
        steps {
            git branch: 'master', url: 'https://github.com/ygminds73/maven-simple-master.git'
        }
    }

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

    stage('Upload to Nexus') {
        steps {
            withMaven(maven: 'M3') {
                sh "mvn clean deploy -s /var/lib/jenkins/.m2/settings.xml -DskipTests"
            }
        }
    }

    stage('Download from Nexus') {
        steps {
            sh """
            curl -u admin:admin@123 -O \
            http://65.2.9.176:8081/repository/maven-releases/com/github/jitpack/maven-simple/0.2-SNAPSHOT/maven-simple-0.2-SNAPSHOT.jar
            """
        }
    }

    stage('Deploy to Nginx') {
        steps {
            sh """
            sudo rm -rf /var/www/html/*
            sudo cp target/maven-simple-0.2-SNAPSHOT.jar /var/www/html/
            sudo systemctl restart nginx
            """
        }
    }
}

}

12. vim /etc/sudoers

jenkins ALL=(ALL) NOPASSWD: /bin/systemctl restart nginx, /bin/rm, /bin/cp or sudo chown -R jenkins:jenkins /var/www/html