Incremental migration plan in Microservices - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Key Benefit of Incremental Migration

Which of the following is the primary benefit of using an incremental migration plan when moving from a monolithic system to microservices?

A It ensures all microservices share the same database schema from the start.

B It requires rewriting the entire system at once to avoid compatibility issues.

C It eliminates the need for any downtime during migration.

D It allows gradual testing and validation of each microservice before full migration.

💡 Hint

Think about how risk is managed during migration.

Incremental migration allows teams to move parts of the system step-by-step, testing each microservice independently to reduce risk and catch issues early.

❓ Architecture

intermediate

Order of Steps in Incremental Migration

What is the correct order of steps in a typical incremental migration plan from monolith to microservices?

A 1,2,3,4

B 3,1,2,4

C 1,3,2,4

D 2,1,3,4

💡 Hint

Think about logical progression from identification to deployment and validation.

First, isolate a capability, then build the microservice, redirect traffic, and finally monitor to ensure success.

❓ scaling

advanced

Handling Data Consistency During Incremental Migration

During incremental migration, what is the best approach to maintain data consistency between the monolith and new microservices?

A Allow both systems to write independently to the same database tables simultaneously.

B Use event-driven architecture with asynchronous messaging to synchronize data changes.

C Stop all writes to the monolith and only write to microservices during migration.

D Duplicate all data manually after migration completes.

💡 Hint

Consider how to keep systems in sync without blocking operations.

Event-driven asynchronous messaging allows both systems to stay updated without tight coupling or downtime.

❓ tradeoff

advanced

Tradeoff of Incremental Migration vs Big Bang

What is a major tradeoff when choosing incremental migration over a big bang migration?

A Incremental migration takes longer but reduces risk and allows continuous delivery.

B Incremental migration requires no changes to existing code.

C Incremental migration guarantees zero bugs after migration.

D Incremental migration eliminates the need for monitoring after deployment.

💡 Hint

Think about time and risk factors.

Incremental migration is slower but safer, allowing teams to deliver continuously and fix issues early.

❓ estimation

expert

Estimating Capacity Needs During Incremental Migration

If a monolithic system handles 10,000 requests per second and you migrate 20% of its functionality to a new microservice, what is the minimum capacity you should provision for the new microservice to handle peak load safely?

A Only 500 requests per second because microservices are more efficient.

B Exactly 10,000 requests per second since all traffic might shift suddenly.

C At least 2,000 requests per second plus a safety margin (e.g., 25%).

D No capacity needed initially; scale only after monitoring.

💡 Hint

Calculate based on percentage of functionality and add buffer for safety.

20% of 10,000 is 2,000 requests per second; adding a safety margin ensures the microservice can handle spikes.