SAP-C02 Continuous Improvement for Existing Solutions Practice Question

A company has a monolithic application running on a single Amazon EC2 instance. The application consists of a web server and a backend worker process. The company wants to migrate to a microservices architecture using containers on Amazon ECS with Fargate. The solutions architect needs to design a solution that minimizes downtime during the migration. Which approach should the solutions architect recommend?

⚠ Common exam trap

SAP-C02 often tests whether candidates recognize that 'minimize downtime' and 'microservices' together rule out big-bang refactors and lift-and-shift containerization — the trap is picking the option that sounds fastest (containerize everything at once) rather than the one that is safest and incremental.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

Use a strangler fig pattern: gradually replace parts of the monolith with microservices, routing traffic via an Application Load Balancer.

The strangler fig pattern incrementally replaces monolith functionality with microservices while keeping the monolith running, routing traffic between old and new components via a load balancer. This allows gradual cutover, rollback capability, and near-zero downtime — exactly what the question asks for. It is the industry-standard approach for low-risk monolith-to-microservices migration.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
Create a Docker image of the entire monolithic application and run it on ECS with Fargate.
Why it's wrong here
Running the whole monolith as one Fargate task keeps the web server and worker coupled, so neither can be scaled or deployed independently — the migration goal is unmet. It is tempting because lift-and-shift containerisation is the fastest route to Fargate, and would suit a scenario where the objective is merely hosting an unchanged application on managed compute.
✓
Use a strangler fig pattern: gradually replace parts of the monolith with microservices, routing traffic via an Application Load Balancer.
Why this is correct
The strangler fig pattern incrementally extracts functionality from the monolith into ECS Fargate microservices, with an Application Load Balancer routing requests between old and new components. This satisfies the minimise-downtime constraint, since both run concurrently and traffic shifts progressively, avoiding a disruptive big-bang cutover.
✗
Run the monolithic application on the same EC2 instance as the new microservices, using different ports.
Why it's wrong here
Co-locating both workloads on one EC2 instance preserves the single point of failure and resource contention the migration was meant to remove. This pattern fits temporary coexistence where shared capacity is acceptable and no resilience requirement exists.
✗
Refactor the entire application into microservices, then deploy all microservices at once on ECS.
Why it's wrong here
A single cutover deploys every microservice simultaneously, so any failure leaves no working version serving traffic and downtime is unavoidable. This suits greenfield builds where no live users depend on continuous availability during the transition.

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SAP-C02 Continuous Improvement for Existing Solutions Practice Question

Why each option matters

Option-by-option breakdown

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