Creating Jenkins pipeline to Build and deploy the Docker Image

 To Understand the Jenkins pipeline and trigger build refer to my previous here. 

Prerequisite.

Install the Following plugins in Jenkins. navigating to ManageJenkins > ManagPlugins

Maven Integration plugin Docker Pipeline

Step1: Create the Docker credentials in Jenkins.

Navigate to Dashboard and  Select Manage Jenkins

Step2: Select Manage credentials.

Step:3 Create Credentials.

Select Stores scoped to Jenkins > Global Credentials > Add Credentials 

Make sure you give some Id to the credentials.

Step:4 Create Pipeline.

pipeline {

  environment {

    registry = "syedghouse14/greet-user-repo"

    registryCredential = 'Docker-Hub'

    dockerImage = ''

    dockerfile="${workspace}\\GreetUser\\Dockerfile"

    pomfile="${workspace}\\GreetUser\\pom.xml"

  }

  agent any

  stages {

    stage('Cloning Git') {

      steps {

        git 'https://github.com/Syed-SearchEndeca/gretuser.git'

        

      }

    }

    stage ('Build') {

steps {

withMaven(maven : 'apache-maven-3.6.3') {

bat "mvn clean package -f ${pomfile}"

}

}

}

    stage('Building image') {

      steps{

        script {

          dockerImage = docker.build registry + ":$BUILD_NUMBER",

          "--file ${dockerfile} ."

        }

      }

    }

    stage('Deploy Image') {

      steps{

        script {

          docker.withRegistry( '', registryCredential ) {

            dockerImage.push()

          }

        }

      }

    }

    stage('Remove Unused docker image') {

      steps{

        bat "docker rmi $registry:$BUILD_NUMBER"

      }

    }

  }

}

Step:5 Execute Success

Things to Consider

Make sure you pass the credentials created in the pipeline.

Pass the Docker File explicitly

 "--file ${dockerfile} ."

You will encounter the following error and resolution for that.

Step 4/5 : COPY GreetUser-0.0.1-SNAPSHOT.jar app.jar
COPY failed: stat /var/lib/docker/tmp/docker-builder619200988/GreetUser-0.0.1-SNAPSHOT.jar: no such file or directory

In One of the step it fails, For this edit the docker file as below.

Initial Docker file.

FROM openjdk:8-jdk-alpine
ARG JAR_FILE=target/*.jar
COPY ${JAR_FILE} app.jar
ENTRYPOINT ["java","-jar","/app.jar"]

Modified Docker file.

FROM openjdk:8-jdk-alpine
RUN addgroup -S spring && adduser -S spring -G spring
USER spring:spring
ENTRYPOINT ["java","-jar","target/*.jar"]
Here I skipped the Copy Step Instead added the target directly. Hope this helps.
Happy Learning !!!!