Microservices Interservice Communication Strategies 2 — Questions and Answers
Question 1: Which communication style introduces the tightest temporal coupling between two microservices?
- Synchronous request/response (Correct answer)
- Asynchronous messaging via a broker
- Event streaming with replay
- Fire-and-forget pub/sub
Correct answer: Synchronous request/response
Synchronous request/response requires both services to be available at the same time, creating temporal coupling.
Question 2: What is the primary benefit of using a message broker like RabbitMQ between services?
- It decouples producers and consumers in time and space (Correct answer)
- It guarantees zero network latency
- It removes the need for serialization
- It eliminates the need for service discovery
Correct answer: It decouples producers and consumers in time and space
A broker buffers messages so producers and consumers do not need to interact directly or simultaneously.
Question 3: In a request/response REST call, which HTTP status code best signals that the caller should retry later?
- 503 Service Unavailable (Correct answer)
- 400 Bad Request
- 404 Not Found
- 401 Unauthorized
Correct answer: 503 Service Unavailable
503 indicates a transient unavailability, making it a retryable condition.
Question 4: Which pattern lets a client make a single call that a gateway fans out to multiple backend services?
- API composition / aggregation (Correct answer)
- Database-per-service
- Strangler fig
- Bulkhead isolation
Correct answer: API composition / aggregation
API composition aggregates results from several services behind one client-facing endpoint.
Question 5: What does gRPC use as its default serialization format?
- Protocol Buffers (Correct answer)
- JSON
- XML
- YAML
Correct answer: Protocol Buffers
gRPC uses Protocol Buffers, a compact binary format, by default.
Question 6: Which approach avoids blocking the caller's thread while waiting for a downstream response?
- Asynchronous (non-blocking) communication (Correct answer)
- Synchronous polling in a loop
- Sequential blocking calls
- Two-phase commit
Correct answer: Asynchronous (non-blocking) communication
Asynchronous communication frees the caller to continue work instead of waiting.
Question 7: Why is point-to-point synchronous chaining of many services often discouraged?
- Latency and failure probability compound across the chain (Correct answer)
- It reduces total network calls
- It guarantees stronger consistency
- It removes the need for timeouts
Correct answer: Latency and failure probability compound across the chain
Each hop adds latency and another point of failure, so long synchronous chains become fragile.
Microservices Interservice Communication Strategies 2
Which communication style introduces the tightest temporal coupling between two microservices?