Microservices Resilience and Fault Tolerance 2

Question 1

In a circuit breaker, what does the HALF-OPEN state primarily do?

Accepted Answer

Allows a limited number of trial requests to test if the service has recovered

Answer

Permanently blocks all traffic to the failing service

Answer

Caches all responses indefinitely

Answer

Doubles the request timeout on every attempt

Question 2

What is the main purpose of the bulkhead pattern in microservices?

Accepted Answer

Isolating resources so a failure in one component cannot exhaust resources used by others

Answer

Encrypting inter-service traffic

Answer

Compressing payloads to save bandwidth

Answer

Automatically scaling pods based on CPU

Question 3

Which retry strategy adds randomness to wait times to avoid synchronized retry storms?

Accepted Answer

Exponential backoff with jitter

Answer

Fixed-interval retry

Answer

Immediate retry

Answer

Linear backoff without jitter

Question 4

A timeout is set too high on a downstream call. What resilience risk does this create?

Accepted Answer

Threads and connections stay occupied longer, risking resource exhaustion under load

Answer

Requests fail too fast for users to notice

Answer

It forces the circuit breaker to never open

Answer

It guarantees retries always succeed

Question 5

What does graceful degradation mean for a microservice under partial failure?

Accepted Answer

The service continues providing reduced or fallback functionality instead of failing entirely

Answer

The service shuts down completely to protect data

Answer

The service replays all failed requests on restart

Answer

The service blocks until the dependency recovers

Question 6

Why is idempotency important when implementing automatic retries?

Accepted Answer

It ensures repeated identical requests do not cause duplicate side effects

Answer

It speeds up the network round trip

Answer

It encrypts the retry payload

Answer

It removes the need for timeouts

Question 7

What is the role of a fallback in a resilience library like Resilience4j or Hystrix?

Accepted Answer

To provide an alternative response when the primary call fails or the circuit is open

Answer

To increase the call timeout automatically

Answer

To log every successful request

Answer

To shard the database