Microservices Cheat Sheet 2026

The 30 highest-yield Microservices facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Why should a CI pipeline fail fast on the first failing stage? → To give quick feedback and avoid wasting resources on a broken build
2. Which pattern aggregates data from multiple services to serve a client-specific view? → Backend for Frontend (BFF) / API composition
3. What does 'mean time to recovery' (MTTR) measure in deployment practice? → How quickly service is restored after a failure
4. The Aggregator pattern is used to do what? → Combine results from multiple services into one response
5. In Kubernetes, which object ensures a specified number of identical Pod replicas are always running? → ReplicaSet
6. What is a 'heartbeat' in the context of a service registry? → A periodic signal an instance sends to renew its registration
7. According to the CAP theorem, a service registry like Eureka favors which properties during a network partition? → Availability and Partition tolerance
8. Which is a recommended pattern for emitting logs from containerized microservices? → Write logs to stdout/stderr and let the platform collect them
9. Which of the following is a potential impact of microservices on a large organization? → It will make cross-team collaboration
10. What is the role of the kube-scheduler? → Assign newly created Pods to suitable nodes
11. What does client-side service discovery require the client to do? → Query a registry and choose an instance itself
12. What is the benefit of trunk-based development for CI/CD? → Frequent small merges to main reduce integration conflicts
13. A timeout is set too high on a downstream call. What resilience risk does this create? → Threads and connections stay occupied longer, risking resource exhaustion under load
14. What is a common cause of missing spans in a distributed trace? → Trace context not propagated across an async boundary or external call
15. In a shadow (dark) deployment, how is the new version exercised? → It receives mirrored production traffic without affecting user responses
16. Microservices have which of the following disadvantages? → Both A and B
17. What are some of the most common technologies for implementing microservices? → Both A and B
18. Which type of test is most effective for detecting issues that only appear when multiple microservices interact together in a realistic environment? → End-to-end tests
19. An orchestration-based saga differs from choreography because it uses a: → Central coordinator that directs each step
20. Why is it important to identify business functions of applications and map similar functions across all of your applications in a microservices strategy? → Because these functions will serve as the targets for microservices creation
21. What is a compensating transaction in a saga? → An action that semantically undoes a prior committed step
22. In a blue-green deployment, what is the role of the 'green' environment before the cutover? → The idle environment running the new version, validated before traffic switches
23. Which approach avoids blocking the caller's thread while waiting for a downstream response? → Asynchronous (non-blocking) communication
24. What makes a microservices-oriented architecture (MOA) different from a service-oriented architecture (SOA)? → All the above
25. What does the Docker instruction EXPOSE accomplish? → Documents which port the container listens on
26. Why might a microservice store a denormalized copy of another service's reference data? → To avoid synchronous calls and improve query autonomy and resilience
27. What is a key advantage of blue-green over rolling deployment? → Instant rollback by switching traffic back to the old environment
28. What is the main drawback of relying heavily on end-to-end tests in a microservices architecture? → They are slow, brittle, and difficult to maintain as the number of services grows
29. Which fallacy of distributed computing warns architects most directly when designing service calls? → The network is reliable
30. In the microservices testing pyramid, which layer should contain the largest number of tests? → Unit tests