AWS Certified Solutions Architect – ProfessionalAccelerate Workload Migration and ModernizationEasy
A large enterprise is planning to migrate a critical, stateful legacy application from on-premises to AWS. The application uses a custom binary protocol for inter-service communication and has strict latency requirements (sub-10ms). The enterprise wants to minimize code changes and maintain existing operational procedures as much as possible during the initial migration phase. Which AWS service is best suited to host this application to meet these requirements?
- AAWS Lambda with API Gateway
- BAmazon Elastic Container Service (ECS) with Fargate
- CAmazon Elastic Kubernetes Service (EKS)
- DAmazon EC2 instances with VPC Peering
Show answer & explanationAnswer & explanation
Correct answer: D. Amazon EC2 instances with VPC Peering
For stateful legacy applications with custom protocols and strict latency requirements, minimizing code changes, and maintaining operational procedures, EC2 instances provide the most flexibility and control. VPC Peering allows for direct, low-latency network connectivity between different VPCs, which might be necessary for hybrid setups or phased migrations.
Why the other options are wrong
- A. AWS Lambda is serverless and event-driven, requiring significant re-architecture for stateful applications and is not suitable for custom binary protocols.
- B. ECS with Fargate is good for containerized applications but might require significant refactoring for a stateful legacy app with custom binary protocols.
- C. EKS is for container orchestration and would require containerizing the application, which goes against minimizing code changes for a legacy stateful app.
Lift and Shift (Rehost)
Migrating an application to the cloud without making significant changes to its architecture. Often involves moving applications from on-premises servers to AWS EC2 instances.
- Minimizes initial migration effort and risk.
- Good for legacy applications with complex dependencies.
- May not fully leverage cloud-native benefits immediately.
Memory trick: Lift and Shift is like moving a whole box without opening it.