dinmamerciboi / jenkins-docker

Integrating Docker within Jenkins

Jenkins-Docker

Integrating Docker within Jenkins

1. Clone this Repository

This Repository contains a Dockerfile that builds a custom Jenkins image, with Docker installed within it.

• The FROM command tells Docker the base image (jenkins/jenkins:lts) from which to build the custom image.
• The first RUN command updates all essential packages using apt-get update. Then installs the new ones needed for the custom Jenkins image using apt-get install.
• The following RUN command downloads the Docker Linux Debian distribution CLI. Then the next one adds it to the repository.
• And the last RUN command adds Jenkins user to the Docker group.

2. Build the Custom Jenkins-Docker Image

With this command, build and tag the custom jenkins-docker image appropriately

docker build -t username/custom-jenkins-docker-image:v

3. Run the Container with the Image

With this command, run the container with the custom jenkins-docker image

docker run --name jenkins-docker -d -p 8080:8080 -p 50000:50000 -v /var/run/docker.sock:/var/run/docker.sock -v jenkins_home:/var/jenkins_home username/custom-jenkins-docker-image:v

4. A few things to note

Store Jenkins data

To store Jenkins, you need to create an explicit volume for Jenkins on your host machine. To do that, the argument -v jenkins_home:/var/jenkins_home was added when running the custom Jenkins-Docker image.

Enabling use of Docker daemon in the Jenkins container

To do this, connect the Docker CLI in the Jenkins container to the Docker daemon on the host machine by bind mounting the daemon’s socket into the container with the -v flag. When running the image, this argument: /var/run/docker.sock:/var/run/docker.sock was added.

5. Configure your Jenkins Environment

• Access Jenkins UI on the web page localhost:8080
• Retrieve the initial password with this command

  docker exec -it jenkins-docker cat /var/jenkins_home/secrets/initialAdminPassword

• Install Suggested Plugins
• Create the First Admin User

6. A Simple Sample Pipeline Script

• Create a Pipeline project
• Paste this sample pipeline script

pipeline{
    agent any
     tools {
        maven "maven3.9.3"
    }
    
    stages{
        stage('1. Git clone'){
            steps{
                sh "echo 'Cloning the latest version of the application'"
                git "https://github.com/MerciBoi/maven-web-application"
            }
        }
        stage('2. Test and Build'){
            steps{
                sh "echo 'Running Unit testing'"
                sh "echo 'Unit testing done. Creating packages.'"
                sh "mvn clean package"
                sh "echo 'Artifacts created'"
            }
        }
        stage('3. Predeployment'){
            steps{
            withCredentials([usernamePassword(credentialsId: 'dockercred', passwordVariable: 'DOCKER_PASS', usernameVariable: 'DOCKER_USER')]) {
                sh "echo 'Predeployment in progress'"
                sh "docker build -t chydinma/test:$BUILD_NUMBER ."
                sh "docker login -u $DOCKER_USER -p $DOCKER_PASS"
                sh "docker push chydinma/test:$BUILD_NUMBER"
                }
            }
        }
        stage('4. Email Notification'){
            steps{
                sh "echo 'Application deployment successful'"
                sh "echo 'Congratulations, end-to-end automation process completed.'"
                emailext (attachLog: true, body: 'The build is complete.', subject: 'Build Complete', to: '[email protected]')
                }
            }
        }
    }

Before you run the build, ensure you do the following

• Install tool Maven, here used as maven3.9.3
• Create Credential for DockerHub login of type Username and Password, here used as dockercred
• Bind the credential dockercred to variables as used in the pipeline script
  • Go to Pipeline syntax generator
  • Use withcredentials: Bind credentials to variables
  • Bindings should be Username and password (separated)
  • Specify Username Variable and Password Variable, here used as DOCKER_USER and DOCKER_PASS respectively
  • Generate Pipeline Script
  • Copy and paste, as shown above
• Notice that Email Notification was configured, you may edit the script to remove that if you have not configured your Jenkins for Email Notification, or otherwise.

7. Now, Run your build!

Hope the build is successful!