My free teacher: GIT: Chapter 15 — Git and DevOps Integration (CI/CD, Infrastructure as Code, Release Automation)

Chapter 15 — Git and DevOps Integration (CI/CD, Infrastructure as Code, Release Automation)

15.1 Introduction

DevOps emphasizes automation, collaboration, rapid delivery, and continuous feedback. Git acts as the foundational coordination layer for DevOps workflows by serving as the authoritative source of truth for:

Application code
Infrastructure configuration
Pipeline definitions
Deployment manifests
Operational scripts

This chapter explores Git’s integration with Continuous Integration (CI), Continuous Delivery/Deployment (CD), Infrastructure as Code (IaC), and automated release management.

15.2 Git as the DevOps Control Plane

In DevOps environments, Git evolves from version control into an orchestration backbone.

Key Roles

Change tracking system
Pipeline trigger mechanism
Configuration repository
Deployment driver
Audit trail provider

Modern DevOps models often adopt GitOps, where system state is defined declaratively in Git and automation reconciles runtime environments.

15.3 Continuous Integration (CI)

15.3.1 Definition

Continuous Integration is the practice of automatically building and testing code upon integration into shared repositories.

Objectives

Early defect detection
Integration conflict reduction
Code quality assurance
Automated verification

15.3.2 Git-Driven CI Triggers

Typical triggers include:

Push events
Pull request creation
Tag creation
Scheduled workflows

These events initiate automated pipelines.

15.3.3 CI Pipeline Stages

Stage	Description
Checkout	Retrieve repository
Build	Compile or package
Test	Execute automated tests
Static analysis	Linting and security scanning
Artifact generation	Produce deployable outputs

15.3.4 CI Tooling Ecosystem

Widely used Git-integrated CI platforms include:

Jenkins
GitHub Actions
GitLab CI/CD
CircleCI

These systems integrate with Git repositories to automate verification workflows.

15.4 Continuous Delivery and Continuous Deployment

15.4.1 Continuous Delivery

Automated preparation of release-ready artifacts while retaining manual approval.

15.4.2 Continuous Deployment

Fully automated production release following successful pipeline completion.

15.4.3 Git Role in CD

Git supports CD by:

Versioning deployment configurations
Managing environment-specific manifests
Triggering release workflows
Providing rollback references

15.5 Infrastructure as Code (IaC)

15.5.1 Concept

Infrastructure as Code treats infrastructure configuration as version-controlled source artifacts.

Examples:

Cloud resource definitions
Container orchestration manifests
Network policies
Server provisioning scripts

15.5.2 Benefits of Git-Managed Infrastructure

Version history
Peer review
Environment reproducibility
Change auditing
Automated provisioning

15.5.3 IaC Tooling

Common IaC tools integrated with Git include:

Terraform
Ansible
AWS CloudFormation
Pulumi

Git repositories store IaC definitions, enabling collaborative infrastructure evolution.

15.6 GitOps Model

15.6.1 Definition

GitOps is an operational model where Git is the single source of truth for both application and infrastructure state.

Core Principles

Declarative configuration
Version-controlled desired state
Automated reconciliation
Continuous convergence

GitOps Workflow

Change configuration in Git
Review and merge
Automation detects change
Environment reconciles to new state

GitOps Tooling

Argo CD
Flux

15.7 Container and Orchestration Integration

Git repositories commonly store container configuration:

Dockerfiles
Kubernetes manifests
Helm charts

Integration examples:

Build container images from commits
Deploy Kubernetes workloads from Git
Version container definitions

15.8 Automated Release Management

15.8.1 Git Tagging Strategy

Tags identify release snapshots.

Types:

Semantic version tags
Build tags
Milestone tags

15.8.2 Release Automation Pipeline

Typical steps:

Tag creation
Artifact build
Release notes generation
Package publishing
Deployment

15.8.3 Semantic Versioning

Standard version format:


MAJOR.MINOR.PATCH

Benefits:

Predictable compatibility
Automated release logic
Dependency management

15.9 Environment Management with Git

15.9.1 Branch-Based Environment Model

Branch	Environment
main	Production
develop	Integration
feature	Development
release	Staging

15.9.2 Configuration Separation

Techniques:

Environment directories
Variable injection
Template rendering
Overlay configuration

15.10 Feature Flags and Progressive Delivery

Git integrates with progressive delivery practices:

Feature flag configuration stored in Git
Controlled rollout via configuration changes
Canary and blue-green deployments driven by Git updates

15.11 Observability and Feedback Loops

Git-based DevOps pipelines often integrate monitoring feedback:

Pipeline metrics
Deployment success indicators
Performance telemetry
Alert-based rollback triggers

Git history provides traceability linking runtime behavior to code changes.

15.12 Security Integration (DevSecOps)

Git-centric security practices include:

Static code scanning
Dependency vulnerability scanning
Container image scanning
Policy enforcement
Infrastructure security validation

Security checks become pipeline stages.

15.13 Monorepo vs Polyrepo in DevOps

Monorepo

Single repository containing multiple services.

Advantages

Simplified dependency visibility
Unified tooling
Cross-service atomic changes

Polyrepo

Multiple repositories per service.