Jenkins Freestyle Project Guide

What is CI/CD?

CI (Continuous Integration) is the practice of automating the integration of code changes from multiple developers into a single codebase. It involves developers frequently committing their work into a central code repository (such as GitHub or Stash).
Automated tools then build the newly committed code and perform tasks like code review, ensuring that the code is integrated smoothly.
The key goals of Continuous Integration are to find and address bugs quickly, make the integration process easier across a team of developers, improve software quality, and reduce the time it takes to release new features.
CD (Continuous Delivery) follows Continuous Integration and ensures that new changes can be released to customers quickly and without errors.
This includes running integration and regression tests in a staging environment (similar to production) to ensure the final release is stable.
Continuous Delivery automates the release process, ensuring a release-ready product at all times and allowing deployment at any moment.

What Is a Build Job?

In Jenkins, a build job is an automated process that manages the various stages of software development, including building, testing, and deploying applications.
It is configured to source the code from a repository, trigger builds based on specific conditions (such as code changes or scheduled times), and define the environment settings necessary for the build.
The build job includes steps to compile the source code, run tests to ensure functionality, and package the code into a distributable format.
Post-build actions can involve archiving the build artifacts, deploying them to staging or production environments, and sending notifications to team members about the build status.
This automation helps ensure consistent, repeatable builds, reduces manual errors, and accelerates the overall development process.

Task 1 : Freestyle project

Create an agent for your app (which you deployed using Docker in a previous task).
Create a new Jenkins freestyle project for your app.
In the "Build" section of the project, add a build step to run the docker build command to build the image for the container.
Add a second step to run the docker run command to start a container using the image created in the previous step.

Create an agent for your app (which you deployed using Docker in a previous task).

Install Jenkins and setup Jenkins, Visit Blog.

Setup agent, Visit Blog.
Below steps on agent,
Install Java and Docker.

Setup of agent on Jenkins UI,

Agent configured for the build.

Create a new Jenkins freestyle project for your app.

In the "Build" section of the project, add a build step to run the docker build command to build the image for the container.

Create index.html file on master as sample source code.

<!-- index.html -->
<!DOCTYPE html>
<html>
<head>
    <title>Welcome to Nginx!</title>
</head>
<body>
    <h1>Hello, Dockerized Nginx!</h1>
</body>
</html>

Create Dockerfile

# Use the official Nginx image from the Docker Hub
FROM nginx:alpine

# Copy the custom index.html to the Nginx default HTML location
COPY index.html /usr/share/nginx/html/index.html

# Expose port 80 to the outside world
EXPOSE 80

# Command to run when the container starts
CMD ["nginx", "-g", "daemon off;"]

Execute shell commands,

echo "Building docker image...."
docker build -t nginx:v1 .

echo "Removing old image...."
docker stop nginx && docker rm nginx

echo "Executing docker container"
docker run -d --name nginx -p 80:80 nginx:v1