A company has a large monolith with tightly coupled modules, a commercial Oracle database, shared file storage, hardcoded server addresses, and Windows-only components. It wants to move to microservices on AWS with low business risk. Which approach is most appropriate?
Show answer and explanation
Answer: C
The strangler fig pattern moves functionality gradually. A gateway routes requests so that migrated services and remaining monolith parts coexist, which lowers risk and allows rollback per feature. SCT and DMS handle the database, shared files move to EFS or S3 to remove local file dependencies, and Application Migration Service carries the Windows components. A one-window move or a simple replatform would keep the coupling, and SaaS replacement is rarely possible for custom business logic.
Why the other options are wrong
- A. A big bang move of tightly coupled components concentrates all risk into one window, and a failure can stop the entire business. It also does not decompose the monolith into services.
- B. Replatforming to containers moves the coupling into containers unchanged. Hardcoded addresses and shared file dependencies remain, so the monolith is not modernized.
- D. Custom business logic seldom has a SaaS equivalent, so repurchasing each component is usually not possible. It also would not produce microservices that the company controls.