Software Architect Guide: AWS CI/CD Pipeline – Rails App Deployment (Multi-Region)

Let’s check AWS CI/CD Pipeline in a clear and structured way — with diagram, services used, and a realistic example for deploying a Ruby on Rails app to multiple AWS regions.

💡 4.1 AWS CI/CD Pipeline – Rails App Deployment (Multi-Region)

🧩 Prompt Recap:

Propose an AWS-based CI/CD pipeline for a Rails application that must deploy to multiple regions. Include services and sequence.

✅ Goal

Deploy a Ruby on Rails app across multiple AWS regions automatically via a CI/CD pipeline. The system should support:

  • Source control
  • Build and test automation
  • Infrastructure provisioning
  • Cross-region deployment

🛠️ Key AWS Services Involved

ServiceRole
CodeCommit or GitHubSource code repository
CodeBuildRuns tests and builds Docker image or artifact
CodePipelineOrchestrates CI/CD steps
ECR (Elastic Container Registry)Stores Docker images
CloudFormation or TerraformDeploys infra (ECS, RDS, etc.)
S3Artifact storage / template sync between regions
SNS or LambdaOptional: notify or trigger region deployments
ECS / EC2 / Elastic BeanstalkRuntime for Rails app
Route 53DNS across regions (optional failover/load balancing)

🧭 Step-by-Step Pipeline (With Regions)

                  ┌────────────────────────┐
                  │   CodeCommit / GitHub  │
                  └─────────┬──────────────┘
                            │ Push
                            ▼
                     ┌────────────┐
                     │ CodePipeline│
                     └─────┬──────┘
                           ▼
                   ┌─────────────┐
                   │ CodeBuild   │
                   │ (Run tests, │
                   │  lint, etc) │
                   └─────┬───────┘
                         ▼
              ┌──────────────────────────┐
              │ Build Docker Image (ECR) │
              └─────┬──────────┬─────────┘
                    ▼          ▼
       ┌──────────────┐   ┌──────────────┐
       │ Deploy to us-east-1            │
       │  (CloudFormation or ECS Fargate│
       └──────────────┘   └──────────────┘
                    ▼          ▼
       ┌──────────────┐   ┌──────────────┐
       │ Deploy to eu-west-1            │
       │  (CloudFormation or ECS Fargate│
       └──────────────┘   └──────────────┘

🧪 Example: Rails App with Docker & ECS

1. Code Commit → CodePipeline Trigger

Use either:

  • CodeCommit repo, or
  • GitHub + webhook to trigger CodePipeline

2. CodeBuild YAML (buildspec.yml)

version: 0.2

phases:
  install:
    runtime-versions:
      ruby: 3.2
      docker: 20
    commands:
      - gem install bundler
      - bundle install
  pre_build:
    commands:
      - echo Logging in to Amazon ECR...
      - $(aws ecr get-login --no-include-email)
  build:
    commands:
      - docker build -t rails-app .
      - docker tag rails-app:latest <account_id>.dkr.ecr.us-east-1.amazonaws.com/rails-app:latest
  post_build:
    commands:
      - docker push <account_id>.dkr.ecr.us-east-1.amazonaws.com/rails-app:latest

artifacts:
  files: "**/*"

3. Deploy to Multiple Regions

You can use:

  • CloudFormation StackSets to deploy same stack (ECS, ALB, etc.) to multiple regions.
  • Or trigger CodeBuild jobs per region via CodePipeline actions or Lambda fan-out.

4. Multi-Region ECS Deployment Example

# CloudFormation ECS Service Definition (us-east-1)
Resources:
  RailsAppService:
    Type: AWS::ECS::Service
    Properties:
      Cluster: arn:aws:ecs:us-east-1:123456789012:cluster/MyCluster
      TaskDefinition: rails-app-task
      DesiredCount: 2

Replicate similar template in eu-west-1, or use StackSet to deploy same stack in both.

📊 Trade-Offs

FactorSynchronous HTTP (Mono-Region)Multi-Region (Eventual)
✅ ResilienceLowHigh
✅ LatencyDepends on regionBetter for global users
🧠 ComplexityLowHigh (requires cross-region handling)
🔁 SyncEasyNeeds S3/CodePipeline replication

✅ Extra Features to Consider

  • 🧪 Test stage in CodePipeline: Use rspec, rubocop, brakeman.
  • 🪣 S3 artifact replication to copy build outputs to target regions.
  • 🚀 Multi-region ECS Blue/Green deployments via CloudFormation hooks or Terraform modules.
  • 📡 Lambda to trigger region-specific pipelines based on deployment result.

🧾 Summary Table

ComponentService
Source ControlCodeCommit or GitHub
CI (tests, build)CodeBuild
CD OrchestrationCodePipeline
Container RegistryECR
Infra DeploymentCloudFormation or Terraform
Region DeploymentsStackSets or regional CodeBuild
Monitoring & RollbackCloudWatch + Lambda