Architecture Diagrams

Visual Patterns & Best Practices

Three-Tier Architecture

Presentation Tier

User interface and load balancing

  • • CloudFront CDN
  • • Application Load Balancer
  • • Public subnets

Application Tier

Business logic and processing

  • • EC2 Auto Scaling Groups
  • • Private subnets
  • • ElastiCache for sessions

Data Tier

Database and storage

  • • RDS Multi-AZ
  • • Database subnets
  • • S3 for static content

Horizontal Scaling

Scale Out

Add more instances to handle load

Stateless Design

No server-side session storage

Load Distribution

Even traffic distribution

Auto Scaling

Dynamic capacity adjustment

Vertical Scaling

Scale Up

Increase instance size/capacity

Downtime Required

Instance restart needed

Hardware Limits

Maximum instance size constraints

Single Point of Failure

Less resilient than horizontal scaling

Global Architecture Patterns

Multi-Region Active-Passive

Primary region with standby for DR

Multi-Region Active-Active

Traffic distributed across regions

CloudFront Global

Edge locations worldwide

Route 53 Failover

DNS-based traffic routing

Architecture Exam Tips

  • • Design for failure - assume components will fail and plan accordingly
  • • Horizontal scaling is preferred over vertical scaling for better availability
  • • Use multiple AZs for high availability within a region
  • • Implement loose coupling between tiers using SQS, SNS, or API Gateway
  • • Store session data externally (ElastiCache/DynamoDB) for stateless design
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