Continuous Delivery Pipeline Using Jenkins

Welcome to this tutorial on building a continuous delivery pipeline using Jenkins. Continuous delivery is the practice of continuously deploying code changes to production, in a safe and automated way. Jenkins is a popular open-source tool that can be used to set up and manage continuous delivery pipelines.

In this tutorial, we will walk through the process of building a continuous delivery pipeline using Jenkins. We will cover the following topics:

1. Installing and configuring Jenkins
2. Creating a Jenkins pipeline
3. Adding testing to the pipeline
4. Deploying to production

1. Installing and configuring Jenkins

The first step in building a continuous delivery pipeline using Jenkins is to install and configure Jenkins. Jenkins can be installed on a variety of operating systems, including Linux, Windows, and macOS.

To install Jenkins on Ubuntu, you can use the following commands:

sudo apt-get update
sudo apt-get install openjdk-8-jdk
wget -q -O - https://pkg.jenkins.io/debian/jenkins.io.key | sudo apt-key add -
sudo sh -c 'echo deb https://pkg.jenkins.io/debian-stable binary/ > /etc/apt/sources.list.d/jenkins.list'
sudo apt-get update
sudo apt-get install jenkins

Once Jenkins is installed, you can access it by opening a web browser and navigating to http://localhost:8080. You will be prompted to enter an initial password, which can be found in the Jenkins logs. Follow the on-screen instructions to set up Jenkins.

Next, you will need to install the necessary plugins for your pipeline. Some plugins that you may find useful include:

• Git plugin: allows Jenkins to interact with Git repositories
• Pipeline plugin: provides a powerful way to create continuous delivery pipelines
• JUnit plugin: allows Jenkins to parse JUnit test results

To install plugins in Jenkins, navigate to the “Manage Jenkins” page and click on “Manage Plugins”. From there, you can search for and install the necessary plugins.

2. Creating a Jenkins pipeline:

Once Jenkins is installed and configured, you can start creating a continuous delivery pipeline. A pipeline in Jenkins is a sequence of stages that define the steps required to build, test, and deploy code changes.

To create a new pipeline in Jenkins, navigate to the “New Item” page and select “Pipeline”. Give your pipeline a name, and click “OK”. You will be taken to the pipeline configuration page.

The pipeline configuration page is where you define the stages and steps of your pipeline. The configuration is written in a domain-specific language (DSL) called Jenkinsfile.

Here is an example Jenkinsfile that defines a simple pipeline:

pipeline {
    agent any
    stages {
        stage('Build') {
            steps {
                sh 'make'
            }
        }
        stage('Test') {
            steps {
                sh 'make test'
                junit 'test-reports/*.xml'
            }
        }
        stage('Deploy') {
            steps {
                sh 'make deploy'
            }
        }
    }
}

This pipeline has three stages: “Build”, “Test”, and “Deploy”. The “Build” stage runs the make command, which builds the code. The “Test” stage runs the make test command and parses JUnit test results from the test-reports/*.xml files. The “Deploy” stage runs the make deploy command, which deploys the code changes to production.

3. Adding testing to the pipeline:

Testing is an important part of any continuous delivery pipeline. It ensures that code changes are safe to deploy to production.

To add testing to your pipeline, you can use the JUnit plugin in Jenkins to parse JUnit test results. The JUnit plugin can be used in the “Test” stage of your pipeline, as shown in the example Jenkinsfile above.

In addition to parsing JUnit test results, you can also add other types of testing to your pipeline, such as integration testing or security testing. Jenkins has a large ecosystem of plugins that can be used to add various types of testing to your pipeline.

4. Deploying to production

Once your code changes have been built and tested, it’s time to deploy them to production. This is typically the final stage of a continuous delivery pipeline.

To deploy to production, you can use a variety of deployment tools, such as Ansible, Chef, or Kubernetes. Jenkins has plugins for many of these tools, allowing you to easily integrate them into your pipeline.

Here is an example Jenkinsfile that deploys code changes using Ansible:

pipeline {
    agent any
    stages {
        stage('Build') {
            steps {
                sh 'make'
            }
        }
        stage('Test') {
            steps {
                sh 'make test'
                junit 'test-reports/*.xml'
            }
        }
        stage('Deploy') {
            steps {
                ansiblePlaybook credentialsId: 'ansible-creds', inventory: 'production', playbook: 'deploy.yml'
            }
        }
    }
}

This pipeline uses the Ansible plugin for Jenkins to deploy the code changes. The ansiblePlaybook step runs the Ansible playbook, which contains the necessary tasks to deploy the code changes.

Types of Software Testing:

1. Unit Testing: It is a type of testing where individual units or components of the software are tested in isolation from the rest of the system. The purpose of unit testing is to verify that each unit of the software code is working as expected.
2. Integration Testing: It is a type of testing where individual software modules are combined and tested as a group. The purpose of integration testing is to verify that the modules work together correctly.
3. System Testing: It is a type of testing where the complete system is tested as a whole. The purpose of system testing is to verify that the system meets the specified requirements.
4. Acceptance Testing: It is a type of testing where the software is tested to ensure that it meets the business requirements and is ready for deployment.
5. Performance Testing: It is a type of testing where the software is tested for its performance characteristics, such as response time, throughput, and resource utilization.

Differences Between Continuous Integration, Delivery, and Deployment:

Continuous Integration (CI), Continuous Delivery (CD), and Continuous Deployment (CD) are all software development practices that aim to improve the efficiency and quality of software development processes.

Continuous Integration (CI) involves continuously merging code changes from multiple developers into a shared repository, verifying the code changes using automated tests, and providing feedback to the developers as quickly as possible. CI helps to catch integration errors and other bugs early in the development cycle, making it easier and faster to fix them.

Continuous Delivery (CD) builds on top of CI and involves continuously delivering software to a staging environment, where it can be tested and validated by stakeholders. CD aims to automate as much of the delivery process as possible, including building, testing, and deploying the software. The goal is to ensure that software is always in a releasable state so that it can be deployed to production at any time.

Continuous Deployment (CD) goes one step further than CD and involves automatically deploying software to production as soon as it passes all tests in the CD pipeline. CD requires a high degree of automation and confidence in the testing and deployment processes and is often used for highly scalable and highly available systems.

Why do We Need Continuous Delivery?

Continuous Delivery is important because it helps to improve the speed, efficiency, and quality of software development. By automating many of the manual and error-prone tasks associated with software delivery, CD helps to reduce the time and effort required to release software and enables teams to respond quickly to customer feedback and market changes.

What Might be The Obvious Cause Of The Failure?

The obvious cause of failure in a CD pipeline is typically a failure in one of the automated tests or deployment steps. If a test fails or a deployment step encounters an error, it can cause the entire pipeline to fail and prevent software from being released to production. To prevent failures, it is important to design the CD pipeline carefully, include thorough testing and validation steps, and monitor the pipeline closely for any errors or issues.

Continuous Delivery Pipeline Using Jenkins:

Jenkins is a popular tool for implementing a CD pipeline. The basic steps in a Jenkins CD pipeline include:

1. Building the software from source code using a build tool like Maven or Gradle.
2. Running automated tests on the software to ensure it meets quality standards.
3. Packaging the software into a deployable artefact, such as a JAR or WAR file.
4. Deploying the artefact to a staging environment for further testing and validation.
5. Promoting the artefact to production if it passes all tests and validation steps.

Conclusion:

In this tutorial, we have walked through the process of building a continuous delivery pipeline using Jenkins. We have covered the installation and configuration of Jenkins, the creation of a pipeline using Jenkinsfile, the addition of testing to the pipeline, and the deployment of code changes to production.

Continuous delivery is a powerful practice that can help you deliver software faster and with fewer errors. By using Jenkins to automate your pipeline, you can streamline your development process and ensure that your code changes are safe to deploy to production.