1. CI/CD Concepts

Continuous Integration (CI)

• Definition: Continuous Integration is the practice of merging developers’ work into the main codebase frequently—often multiple times a day—and running automated builds and tests to detect issues early.
• Key Objectives:
  • Early Bug Detection: Find and fix integration conflicts, broken dependencies, or failing tests sooner.
  • Improved Collaboration: Encourage small, incremental changes so multiple developers can work in parallel with minimal merge conflicts.
  • Faster Feedback Loop: Automated tests notify developers immediately when a change breaks the build.

Continuous Deployment (CD)

• Definition: Continuous Deployment automates the release process, pushing code changes to production (or another target environment) as soon as they pass all required checks and tests.
• Key Objectives:
  • Frequent, Reliable Releases: Reduce manual intervention, speed up the release cycle, and minimize human error.
  • Consistent Environments: Ensure that testing, staging, and production environments are in sync, preventing “works on my machine” issues.
  • Customer Value Delivery: Continuously deliver new features and fixes, enhancing user satisfaction and responsiveness to market changes.

Continuous Delivery vs. Continuous Deployment

• Continuous Delivery: The pipeline is fully automated up to the point of staging or a final approval step; deploying to production can be a manual or automated decision.
• Continuous Deployment: Every successful build (passing all checks) is automatically deployed to production without requiring manual intervention.

2. Building Basic Pipelines

A pipeline is a series of automated steps—such as code checkout, build, test, and deployment—that code changes move through on their way to production. Below are common CI/CD tools and the typical structure of a pipeline.

Popular CI/CD Tools

1. Jenkins

• Overview: One of the earliest and most widely used open-source automation servers.
• Key Features:
  • Huge plugin ecosystem (Git, Docker, Kubernetes, etc.).
  • Master/agent architecture for distributed builds.
  • Highly customizable configuration, though sometimes more complex to maintain.