Day 23 Task: Jenkins Freestyle Project for DevOps Engineers.

Introduction

In the dynamic realm of software development, Continuous Integration (CI) and Continuous Delivery (CD) play pivotal roles in streamlining the development pipeline, enhancing collaboration, and ensuring the swift and error-free delivery of software updates. This article delves into the concepts of CI/CD and explores the use of Jenkins, a popular automation tool, to facilitate these practices. Additionally, we'll take a closer look at Freestyle Projects in Jenkins and how they can be employed to automate various tasks.

Understanding CI/CD

Continuous Integration (CI): CI involves the automated integration of code changes from multiple developers into a central code repository. Developers commit their work regularly, triggering automated tools to build the code, perform code reviews, and ensure the early detection and resolution of bugs. The primary goals of CI are to enhance code quality, simplify collaboration among developers, and expedite the release of new features.

Continuous Delivery (CD): Building upon CI, CD ensures the swift and error-free release of software changes to end-users. It involves running integration and regression tests in a staging environment to validate the release. Automation is a key aspect of CD, ensuring a release-ready product at all times, and enabling deployment at any point.

The Role of Jenkins Build Jobs

In the CI/CD ecosystem, Jenkins plays a crucial role in automating the building, testing, and deployment processes. Jenkins build jobs encapsulate configurations for specific tasks within the application building process. These tasks encompass gathering dependencies, compiling code, archiving, testing, and deploying in different environments.

Jenkins supports various types of build jobs, including freestyle projects, pipelines, multi-configuration projects, folders, multibranch pipelines, and organization folders.

Exploring Freestyle Projects

What is a Freestyle Project? A freestyle project in Jenkins is a versatile project type allowing developers to build, test, and deploy software with a range of configuration options. Here, we'll embark on two tasks to illustrate the capabilities of freestyle projects.

Task-01: Creating an Agent and Freestyle Project for Dockerized Apps

In the ever-evolving landscape of software development, the efficient deployment and management of applications are paramount. In this tutorial, we'll explore Task-01, focusing on creating an agent for your Dockerized app and setting up a Jenkins freestyle project to automate Docker operations.

Step 1: Create an Agent for Your App

Assuming you've deployed your application using Docker, the first step is to create an agent to manage subsequent tasks. An agent in Jenkins acts as a computational resource capable of running tasks on behalf of the master Jenkins instance.

1. Open Jenkins and navigate to "Manage Jenkins" > "Manage Nodes and Clouds."
2. Click on "New Node" to create a new agent. Configure the agent details, specifying the connection details and labels as needed.
3. Save the configuration to add the agent.

Step 2: Create a Freestyle Project

Now, let's set up a Jenkins freestyle project to automate the building and running of your Dockerized app.

1. From the Jenkins dashboard, click on "New Item" to create a new project.
2. Enter a project name and choose the "Freestyle project" option.
3. In the project configuration, go to the "Build" section.

Step 3: Add Build Steps for Docker Operations

In the "Build" section of the project configuration, we'll add two build steps:

Build Step 1: Docker Build

Add a build step to execute the "docker build" command, constructing the image for the container.

"docker build -t your-app-image ."        

Make sure to replace "your-app-image" with the actual name you want for your Docker image.

Build Step 2: Docker Run

Add a second build step to run the "docker run" command, starting a container using the image created in the previous step.

"docker run -d --name your-app-container -p 8080:80 your-app-image"        

Replace "your-app-container" and "your-app-image" with your preferred container and image names.

Save the project configuration.

Task-02: Orchestrating Containers with Docker-Compose

Step 1: Create Jenkins Project for Docker-Compose

In Task-02, we'll create a Jenkins project to handle the orchestration of multiple containers defined in a Docker Compose file.

1. Follow the steps outlined in Task-01 to create a new freestyle project in Jenkins.
2. In the project configuration, navigate to the "Build" section.

Step 2: Add Build Steps for Docker-Compose Operations

Build Step 1: Docker-Compose Up

Add a build step to execute the "docker-compose up -d" command, initiating the deployment of multiple containers defined in the compose file.

"docker-compose up -d -f path/to/your/docker-compose-file.yml"        

Ensure to replace "path/to/your/docker-compose-file.yml" with the actual path to your Docker Compose file.

Build Step 2: Cleanup with Docker-Compose Down

To ensure a clean environment, set up a cleanup step in the Jenkins project.

Add a build step to run the "docker-compose down" command, stopping and removing the containers defined in the compose file.

"docker-compose down -f path/to/your/docker-compose-file.yml"        

Replace "path/to/your/docker-compose-file.yml" with the correct path.

Save the project configuration.