Cloud Architecture Patterns — Overview
What are Architecture Patterns?
Proven design approaches for building reliable, scalable, and cost-efficient systems on cloud. Unlike tool guides, patterns describe how multiple services work together.
AWS Well-Architected Framework (6 Pillars)
| Pillar | Key Question |
|---|
|--------|-------------|
| Operational Excellence | Can you run and monitor? Do you have runbooks? |
|---|---|
| Security | Who can do what? Is data encrypted? |
| Reliability | Can you recover from failure? Do you test failure? |
| Performance Efficiency | Right resource for the job? |
| Cost Optimization | Paying for what you use? |
| Sustainability | Minimum environmental impact? |
Core Patterns
Multi-AZ Active-Active
Both availability zones serve traffic simultaneously. RDS automatic failover in ~60 seconds. Zero data loss with synchronous replication.
Hub-and-Spoke Networking
Transit Gateway connects Dev, Staging, Production VPCs to shared services (monitoring, DNS, logging) and on-premises. No VPC peering mesh complexity.
Strangler Fig (Migration Pattern)
API Gateway routes specific paths to new microservices while the legacy monolith handles the rest. Migrate one domain at a time — no big-bang rewrite.
CQRS (Command Query Responsibility Segregation)
Saga Pattern (Distributed Transactions)
Replace 2-phase commit with compensating transactions. Each microservice publishes events. On failure, compensating events undo completed steps.
Serverless Event-Driven
S3 upload triggers Lambda which processes, stores in DynamoDB, and sends SNS notification. No servers to manage, scales from zero to millions automatically.
Choosing the Right Pattern
| Scenario | Pattern |
|---|
|---------|---------|
| 99.99% uptime required | Multi-AZ Active-Active |
|---|---|
| Microservices with transactions | Saga + CQRS |
| Legacy to cloud migration | Strangler Fig |
| High read, low write traffic | CQRS + Read Replica + Redis |
| Event-driven, unpredictable load | Serverless + EventBridge + SQS |