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Top 31 MicroServices Interview Questions and Answers

12/Oct/2021 | 12 minutes to read

design

Here is a List of essential MicroServices Interview Questions and Answers for Freshers and mid level of Experienced Professionals. All answers for these MicroServices questions are explained in a simple and easiest way. These basic, advanced and latest MicroServices questions will help you to clear your next Job interview.

MicroServices Interview Questions and Answers

These questions are targeted for MicroServices Architecture. You must know the answers of these frequently asked MicroServices interview questions to clear the interview. You will find many questions related to DDD (Domain-Driven Design). MicroServices are technology agnostics so these interview answers apply to Spring Boot MicroServices, .Net MicroServices, Node.js MicroServices, Java MicroServices or any other MicroService Architecture. These questions and answers will help you to clear an interview for Java Developer .Net Developer, Software Architect or any other.

1. What is MicroServices? Explain MicroServices Architecture?

MicroService is:
  • A system of applications that collaborate.
  • An autonomous service - means one MicroService has complete responsibility for one business capability.
  • Partitioned on business domain not technology.
  • Technology agnostic synchronous and asynchronous communication.
For more refer Microservices and Microservice Architecture.

2. What are the Characteristics of a MicroService Architecture?

MicroService Architecture is different from monolithic design and follows some principles as below.
  • Componentization via Services
  • Organized around Business Capabilities
  • Products not Projects
  • Smart endpoints and dumb pipes
  • Decentralized Governance
  • Decentralized Data Management
  • Infrastructure Automation
  • Design for failure
  • Evolutionary Design
For more about these characteristics visit Characteristics of a Microservice Architecture.

3. What do you understand about Decoupling in MicroServices?

A MicroService service is responsible for one business capability in a particular domain. When you have a monolithic architecture it becomes difficult to manage the application infrastructure, deployment and delivery because a monolithic application comprises many tightly coupled layers such as UI, back-end, database etc. In MicroServices Architecture, Decoupling allows you to decouple the business capability which is important to business and changes frequently. Developers, Architects should keep certain points in mind while thinking about decoupling.
  • Decouple the business capability not the code.
  • Decouple the capability that changes frequently and is important to business.
  • Decouple vertically and release them early - vertical components carry user related functionality and are visible to users.
  • First go for Macro then Micro services - identify the business capabilities around a business domain and break down each capability to a MicroService.
For more visit Break a Monolith into MicroServices.

4. What do you understand about Autonomous of a MicroService?

A MicroService is independent of other services, easier to deploy, maintain and can be developed by a small team or one member. If anything goes wrong with a MicroService it does not cause system failures since the MicroServices are autonomous.

4. What do you understand about the Cohesive of a MicroService?

MicroServices have a tendency to be as cohesive as possible. Cohesion is the way to identify how to group related functionalities if they are part of the same domain and how to break apart or delegate to different MicroService if the functionality belongs to a different domain boundary. A high cohesive MicroService follows a single responsibility principle as It implements or group relation functionality and independent functionality is developed by other MicroService. For more visit Identify domain model boundaries and MicroServices Properties.

5. What is Bounded Context?

Bounded Context is a pattern that is used in DDD - Domain-Driven Design. It's a part of DDD and deals with large domain models. Domain model is an object model which incorporates both data and behavior. DDD deals with these large domain models by dividing them into Bounded contexts. In other words, One MicroService is implemented for one bounded context or one domain model. For more visit - BoundedContext.

6. What is Domain-Driven Design? Or MicroService is DDD specific?

DDD (Domain-Driven Design) means - design an application based on models of underlying domain. A model consists of both data and behavior of the domain. MicroServices are DDD specific, means - One service is responsible for the implementation of one domain-model.
For example, there are two domain models Sales and Support then DDD will deal with this situation by dividing these models into two bounded contexts. Hence you need two explicitly interconnected MicroServices for these two different bounded contexts.

7. MicroServices are technology agnostic. Explain it.

In MicroServices architecture, services use the technology agnostic protocols such as HTTP to communicate over the network. MicroServices can be developed using any tech stack such as Java, .NET, Node.js, any hardware or software which best fits to the requirement.

8. What are the benefits of MicroServices?

MicroServices Architecture offers many benefits because of its characteristics.

  • Agility - MicroServices are owned by small, independent teams who have a good understanding of business context so that they can deliver quickly. It empowers you to shorten the development time of a service.
  • Flexible Scaling - You can scale a MicroService independently to meet the demand of application. You can control the infrastructure, cost, availability of a business functionality without affecting other services.
  • Easy Deployment - MicroServices relies on continuous integration and continuous delivery. It allows you to push new features very quickly and you can roll-back the code anytime if anything goes wrong.
  • Technological Freedom - You can develop a MicroService using any tool or technology which best fits your requirement. Again, MicroServices are technology agnostic.
  • Reusable Code - MicroServices allows you to write the code or services which can work as components for other business functionality.
  • Resilience - MicroServices are developed with failures in mind - if anything goes wrong with one service then It will not impact other services or it will not crash the entire system instead of degrading just one failure service functionality.
For more visit Benefits of MicroServices.

9. What do you understand about Resiliency in MicroService Architecture?

Resiliency refers to the ability of a service to recover from failures and continue to function in previous state. It does not mean to avoid the failures but accepting the fact that failures are certain in Cloud based applications and responding to them in a way that there should be minimal data loss and downtime. The Primary goal of resiliency is that a system or application should return to a fully functioning state after a failure.
You should design your systems to be resilient to partial failures like Network outage, VMs crashes which will certainly occur eventually. For more visit Resiliency in MicroServices.

10. What are key Principles of MicroServices?

We have already explained key Characteristics of a MicroService Architecture in question number 2, please go through with that.
Additionally, MicroService design has IDEALS Principles similar to Object oriented design has SOLID principles.

  • I - Interface Segregation Principle
  • D - Deployability (is on you) Principle
  • E - Event-Driven Principle
  • A - Availability over Consistency Principle
  • L - Loose-Coupling Principle
  • S - Single Responsibility Principle
  • For more about it you can refer Microservice design Principles - IDEALS

Related Interview Question Links

11. What are the key characteristics of MicroService?

12. What do you understand by Partitioning?

13. Explain Domain Partitioning?

14. What do you understand about isolation and Autonomous for MicroService?

15. What things do you need to keep in mind in MicroServices Architecture?

16. Shall we split our business logic and CRUD operations into separate micro services to make the crud services generic in nature ?

17. How to avoid maintenance overhead if we have to deploy independent environments for thousands of clients with the help of MicroServices?

18. Often there exists data that needs to be shared among MicroServices. How do we tackle this apart from replicating that entire dataset to each service?

19. How to take care of essential requirement changes in MicroServices?

20. How to upgrade a Service?

21. Differentiate Monoliths vs MicroServices.

22. How to ensure Authentication and Authorization in different MicroServices?

23. How does Client‑Side Discovery Pattern work?

24. How to design a MicroServices Architecture for Failure?

25. How will you monitor a MicroService?

26. What is the role of Domain understanding in MicroService?

27. Develop MicroService with .NET

It's a YouTube video explaining how to develop MicroService with .NET Build Your First Microservice with .NET

Some General Interview Questions for MicroServices

1. How much will you rate yourself in MicroServices?

When you attend an interview, Interviewer may ask you to rate yourself in a specific Technology like MicroServices, So It's depend on your knowledge and work experience in MicroServices.

2. What challenges did you face while working on MicroServices?

This question may be specific to your technology and completely depends on your past work experience. So you need to just explain the challenges you faced related to MicroServices in your Project.

3. What was your role in the last Project related to MicroServices?

It's based on your role and responsibilities assigned to you and what functionality you implemented using MicroServices in your project. This question is generally asked in every interview.

4. How much experience do you have in MicroServices?

Here you can tell about your overall work experience on MicroServices.

Conclusion

We have covered some frequently asked MicroServices Interview Questions and Answers to help you for your Interview. All these Essential MicroServices Interview Questions are targeted for mid level of experienced Professionals and freshers.
While attending any MicroServices Interview if you face any difficulty to answer any question please write to us at info@qfles.com. Our IT Expert team will find the best answer and will update on the portal. In case we find any new MicroServices questions, we will update the same here.