CI/CD Pipeline on AWS Using CodePipeline.

Introduction

Modern applications demand fast, reliable, and repeatable deployments. Manual deployments are error-prone, slow, and difficult to scale. This is where CI/CD (Continuous Integration and Continuous Deployment) comes in.

In this blog, we’ll walk through building a complete CI/CD pipeline on AWS using CodePipeline, along with CodeBuild, CodeDeploy, IAM, and S3. We’ll also cover architecture, best practices, security, and common interview questions around AWS CI/CD.

By the end, you’ll understand:

• How AWS CodePipeline works
• How CI/CD stages are connected
• How to deploy applications automatically
• Real-world design considerations

What is CI/CD?

Continuous Integration (CI)

CI is the practice of:

• Automatically building code
• Running unit tests
• Validating every code commit

Continuous Deployment (CD)

CD automates:

• Deployment to test or production environments
• Rollbacks in case of failure
• Zero-downtime deployments

Together, CI/CD ensures faster releases, better code quality, and reduced human error.

Why Use AWS for CI/CD?

AWS provides fully managed CI/CD services, meaning:

• No servers to manage
• High availability
• Native integration with AWS services
• IAM-based security

Key AWS CI/CD services:

• AWS CodePipeline – Orchestration
• AWS CodeBuild – Build & test
• AWS CodeDeploy – Deployment
• Amazon S3 – Artifact storage
• IAM – Access control
• CloudWatch – Monitoring & logs

What is AWS CodePipeline?

AWS CodePipeline is a fully managed CI/CD orchestration service that automates the build, test, and deploy phases of your release process.

Key Features

• Event-driven (triggers on code changes)
• Visual pipeline stages
• Supports multiple environments
• Integrates with GitHub, CodeCommit, S3
• Supports manual approvals

CI/CD Pipeline Architecture on AWS

High-Level Architecture

1. Source Stage
   • GitHub / CodeCommit repository
2. Build Stage
   • CodeBuild compiles code and runs tests
3. Artifact Storage
   • Build artifacts stored in S3
4. Deploy Stage
   • CodeDeploy deploys to EC2 / ECS / Lambda

Developer → Git Repo → CodePipeline
              ↓
          CodeBuild
              ↓
           S3 Artifacts
              ↓
          CodeDeploy → EC2

Step-by-Step CI/CD Pipeline Setup

Step 1: Source Stage (Git Repository)

The pipeline starts when a developer pushes code to:

• GitHub
• AWS CodeCommit
• Amazon S3

Best Practices

• Use branch-based pipelines (dev, staging, prod)
• Protect main/master branches
• Use webhook triggers instead of polling

Step 2: Build Stage Using AWS CodeBuild

AWS CodeBuild compiles source code, runs tests, and produces artifacts.

buildspec.yml Example

version: 0.2

phases:
  install:
    runtime-versions:
      nodejs: 18
  build:
    commands:
      - npm install
      - npm test
      - npm run build
artifacts:
  files:
    - '**/*'

Key Concepts

• Build environments are ephemeral
• Pay only for build minutes
• Logs stored in CloudWatch

Step 3: Artifact Management with S3

Build artifacts are stored in Amazon S3.

Why S3?

• Durable
• Versioned
• Encrypted at rest
• Integrated with CodePipeline

Security Tips

• Enable bucket versioning
• Use SSE-S3 or SSE-KMS encryption
• Restrict bucket access via IAM

Step 4: Deployment Using AWS CodeDeploy

AWS CodeDeploy automates deployment to:

• EC2
• ECS
• Lambda

appspec.yml Example (EC2)

version: 0.0
os: linux
files:
  - source: /
    destination: /var/www/html
hooks:
  AfterInstall:
    - location: scripts/install.sh
  ApplicationStart:
    - location: scripts/start.sh

Deployment Strategies

• In-place deployment
• Blue-Green deployment
• Canary deployment

IAM Roles and Permissions

IAM is critical for securing CI/CD pipelines.

Required IAM Roles

• CodePipeline service role
• CodeBuild execution role
• CodeDeploy role
• EC2 instance profile

IAM Best Practices

• Follow least privilege
• Separate roles per service
• Avoid wildcard permissions
• Rotate credentials

Monitoring and Logging

CloudWatch Integration

• CodeBuild logs
• Pipeline execution status
• Deployment health

Alarms

• Build failures
• Deployment failures
• Rollback events

Monitoring ensures quick incident response and pipeline reliability.

Common CI/CD Design Patterns

Multi-Account Pipeline

• Dev account
• Staging account
• Production account

Manual Approval Gates

• Required before production deployment

Infrastructure as Code

• Use CloudFormation or Terraform
• Version infrastructure with application code

Cost Optimization Tips

• Use smaller CodeBuild compute types
• Stop unused pipelines
• Use build caching
• Avoid over-triggering builds
• Clean old S3 artifacts

Security Best Practices

• Encrypt artifacts
• Use IAM roles, not access keys
• Enable CloudTrail
• Scan dependencies during build
• Restrict production deployments

Common AWS Interview Questions (Based on This Pipeline)

Q: What is CodePipeline?
A: A managed CI/CD orchestration service that automates build, test, and deployment workflows.

Q: Difference between CodeBuild and CodeDeploy?
A: CodeBuild compiles and tests code; CodeDeploy handles deployment.

Q: How do you secure a CI/CD pipeline?
A: IAM least privilege, encryption, approvals, logging, and monitoring.

Q: How do you implement rollback?
A: Use CodeDeploy with automatic rollback on failure.

Conclusion

Building a CI/CD pipeline on AWS using CodePipeline enables:

• Faster deployments
• Improved reliability
• Better security
• Scalable DevOps practices

This architecture is production-ready, cost-effective, and highly interview-relevant. Writing and implementing this pipeline demonstrates real-world AWS DevOps experience, not just theoretical knowledge.

• This tutorial is just the beginning learn AWS & DevOps hands-on with our complete course and level up your skills.”