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Monolith to Microservices Migration

Overview​

Modernizing legacy monolithic applications into microservices enables scalability, resilience, and faster delivery.

Architecture Evolution​

Monolith​

  • Single codebase
  • Tight coupling
  • Hard to scale

Microservices​

  • Independent services
  • Scalable & fault-isolated
  • Faster deployments

Migration Strategy​

Step 1: Domain Identification​

  • Break into bounded contexts
  • Identify service boundaries

Step 2: Strangler Pattern​

  • Gradually replace monolith
  • Route traffic via API Gateway

Step 3: Data Separation​

  • Move from shared DB → per-service DB

AWS Architecture​

  • Ingress: ALB → Istio Gateway
  • Compute: AWS EKS
  • Service Mesh: Istio
  • CI/CD: GitHub Actions + ArgoCD
  • Database: RDS / Aurora

Implementation Steps​

1. Setup EKS Cluster​

  • Multi-AZ cluster
  • Node groups or Karpenter

2. Containerization​

  • Dockerize services
  • Push to ECR

3. CI/CD Pipeline​

  • Build → Scan → Push → Deploy

4. GitOps​

  • ArgoCD sync from Git

Challenges & Solutions​

ChallengeSolution
Data consistencyEvent-driven architecture
Service communicationIstio / API Gateway
MonitoringPrometheus + NewRelic

Outcome​

  • 10x scalability
  • Faster deployments
  • Improved reliability