In this section, we will explore how Git integrates into the DevOps lifecycle. DevOps is a set of practices that combines software development (Dev) and IT operations (Ops) to shorten the development lifecycle and deliver high-quality software continuously. Git plays a crucial role in this process by providing version control, collaboration, and automation capabilities.

• Definition: Continuous Integration is the practice of merging all developers' working copies to a shared mainline several times a day.
• Role of Git: Git repositories are used to store the codebase. CI tools like Jenkins, Travis CI, and CircleCI monitor these repositories for changes and automatically build and test the code.

• Definition: Continuous Delivery is the practice of keeping the codebase deployable at any point or ensuring that it can be released to production at any time.
• Role of Git: Git tags and branches are used to mark release points. CD tools automate the deployment process, ensuring that the code is always in a deployable state.

• Definition: Infrastructure as Code is the practice of managing and provisioning computing infrastructure through machine-readable definition files, rather than physical hardware configuration or interactive configuration tools.
• Role of Git: Infrastructure code is stored in Git repositories, allowing version control, collaboration, and rollback capabilities.

1. Install Jenkins: Follow the official Jenkins installation guide for your operating system.
2. Create a Git Repository: Initialize a new Git repository or use an existing one.
3. Configure Jenkins:
   • Install the Git plugin in Jenkins.
   • Create a new Jenkins job and configure it to pull from your Git repository.
   • Set up build triggers to start the build process whenever changes are pushed to the repository.
4. Write a Jenkinsfile: This file defines the CI pipeline.

   pipeline {
       agent any
       stages {
           stage('Build') {
               steps {
                   sh 'make build'
               }
           }
           stage('Test') {
               steps {
                   sh 'make test'
               }
           }
       }
   }
   

5. Commit and Push: Commit the Jenkinsfile to your Git repository and push the changes.
6. Monitor Builds: Jenkins will automatically start the build process whenever changes are detected in the repository.

1. Install Terraform: Follow the official Terraform installation guide.
2. Create a Git Repository: Initialize a new Git repository for your infrastructure code.
3. Write Terraform Configuration: Create a main.tf file with your infrastructure configuration.

   provider "aws" {
       region = "us-west-2"
   }
   
   resource "aws_instance" "example" {
       ami           = "ami-0c55b159cbfafe1f0"
       instance_type = "t2.micro"
   }
   

4. Commit and Push: Commit the Terraform configuration to your Git repository and push the changes.
5. Apply Configuration: Use Terraform to apply the configuration.

   terraform init
   terraform apply
   

1. Create a GitHub Repository: Create a new repository on GitHub.
2. Write a .travis.yml File: This file defines the CI pipeline for Travis CI.

   language: python
   python:
     - "3.8"
   install:
     - pip install -r requirements.txt
   script:
     - pytest
   

3. Commit and Push: Commit the .travis.yml file to your GitHub repository and push the changes.
4. Enable Travis CI: Link your GitHub repository to Travis CI and enable builds.
5. Monitor Builds: Travis CI will automatically start the build process whenever changes are detected in the repository.

1. Install Ansible: Follow the official Ansible installation guide.
2. Create a Git Repository: Initialize a new Git repository for your Ansible playbooks.
3. Write an Ansible Playbook: Create a playbook.yml file with your configuration.

   - hosts: all
     tasks:
       - name: Install Nginx
         apt:
           name: nginx
           state: present
   

4. Commit and Push: Commit the Ansible playbook to your Git repository and push the changes.
5. Run Playbook: Use Ansible to run the playbook.

   ansible-playbook -i inventory playbook.yml
   

In this section, we explored how Git integrates into the DevOps lifecycle, focusing on Continuous Integration, Continuous Delivery, and Infrastructure as Code. We provided practical examples using Jenkins, Terraform, Travis CI, and Ansible to demonstrate these concepts. By mastering these techniques, you can streamline your development and operations processes, ensuring faster and more reliable software delivery.