Top Microservices Interview Questions
The following is a collection of the most common Microservices Interview questions for freshers and the best possible answers.
1. What are microservices, and why should someone consider using them?
Microservices is an architectural style or method for building applications. The microservice design enables large and sophisticated applications to be delivered quickly, often, and reliably. Because it is distributed and loosely connected, changes in one team will not break the entire app.
Suppose you have a business focus and want to solve a use case or a problem efficiently without technology constraints. You want to scale an independent service indefinitely, highly available stateless services that are easy to maintain and manage and independently testable. In that case, Microservices architecture is the way to go.
2. What are the most significant benefits of using microservices?
The most notable advantage of using microservices is that it allows you to create an application that collects small autonomous services designed for a specific business area. As a result, if the business requires frequent changes, the development teams may quickly create new app components to fulfill the need.
Business goals are achieved when each microservice runs its process and communicates using a well-defined, lightweight method, such as a container. It also enables an organization's technology stack to evolve.
3. What are the features of Microservices?
The following are the features of microservice
Decoupling – Within a system, services are largely disconnected. As a result, the entire application may be easily constructed, modified, and scaled.
Componentization - Microservices are stand-alone components that can be readily upgraded and changed.
Business Capabilities - Microservices are small, specialized applications that focus on a particular capability.
Autonomy - Developers and teams can operate independently, which speeds up the process.
Continuous Delivery - Allows for frequent software releases by automating software creation, testing, and approval.
Responsibility - Microservices aren't focused on projects as much as they are on applications. Instead, they viewed apps as if they were goods that they were in charge of.
Decentralized Governance - The emphasis is on selecting the best tool for the job. That is to say, there is no standardized or technological pattern. Developers have complete control over which tools they choose to tackle their difficulties.
Agility - Microservices make development more agile. Any new feature can be developed fast and then rejected.
4. What are the main components of Microservices?
The following is a list of the essential Microservices or Microservice architecture components.
Containers, Clustering, and Orchestration
IaC (Infrastructure as Code Conception)
Cloud Infrastructure
API Gateway
Enterprise Service Bus
Service Delivery
5. When should one consider a microservice kind of architecture?
There are two cases.
Suppose you already have a monolithic application. It has grown where scalability issues have arisen, or we cannot reuse components/modules/services across several projects/platforms. In that case, there is a need to do so. At the same time, adding new features is time-consuming and error-prone, making it tough to grow further.
We can think of a business case to be efficiently developed, which can be easily maintainable, tested, and scalable in the future and may be used across multiple projects/products/platforms at the same time for new applications where implementation has not yet begun.
6. What are the main challenges in Microservice Deployment?
Microservices can present both technical and functional issues.
The following are the primary obstacles from a business standpoint.
Require heavy investment
Heavy Infrastructure Setup
Excessive Planning for managing operations overhead
Staff Selection and Maintenance.
From a technical standpoint:
Communication between different microservices in the application.
Component automation
Application maintenance
Configuration Management
Heavy Operations Overhead
Deployment Challenges
Testing and Debugging Challenges
7. What are the three commonly used tools for Microservices?
The three most often used Microservices tools are as follows:
Wiremock
Docker
Hysrix
8. What are the different strategies of Microservices Deployment?
The different strategies of microservices deployment are:-
Multiple Service Instance per Host: Run a single or numerous application service instances on a single/multiple physical/virtual host.
Service Instance per Host: Run a service instance per host
Service Instance per Container: Each service instance should be run in its own container.
Serverless Deployment: Create a ZIP file of the service and upload it to the Lambda function. The Lambda function is a stateless service that automatically runs enough microservices to handle all requests.
9. Explain three types of Tests for Microservices?
Microservice architecture tests are classified into three groups:
We can execute a generic test at the lowest level, such as performance and unit tests. This type of test is completely automated.
We can do exploratory testing like stress tests and usability tests at the middle level.
We can conduct acceptance tests at the highest level, often smaller in number. It also assists stakeholders in learning about various software functionalities.
10. What do you understand by Monolithic Architecture?
Monolithic architecture is similar to a large container that holds all of an application's software components. Within the application, these programs are bundled into a single package.
11. What do you understand by Spring Cloud?
Spring Cloud is a piece of integration software that allows you to connect to external services. It enables a microservices architecture to create apps with limited data processing capabilities.
12. What are some well-known businesses that use Microservice architecture?
Microservices architecture is used by most large-scale software organizations and websites, such as Twitter, Netflix, and Amazon, instead of a monolithic design.
13. What are the challenges faced while using Microservices?
Some of the challenges faced while using microservices are:-
Microservices are constantly interdependent. As a result, they must communicate with one another.
It's a complicated model because it's a distributed system.
If you're going to use Microservice architecture, be prepared for some operations overhead.
To handle heterogeneously dispersed microservices, you'll require trained professionals.
14. What is the difference between SOA, Monolithic, and Microservices Architecture?
The main differences between SOA, Monolithic, and Microservices Architecture are:
Monolithic Architecture: Different components of an application, including the user interface, business logic, and data access layer, are merged into a single platform or programme in a monolithic architecture.
SOA (Service Oriented Architecture): Individual components in an SOA (Service Oriented Architecture) are freely connected and execute a discrete purpose. The jobs of service provider and service consumer are the two most important. Modules may be integrated and reused in SOA, making it versatile and dependable.
Microservices Architecture: It is a sort of SOA in which a set of self-contained components are constructed and merged to form an application. APIs are used to connect these components. This method focuses on business priorities and capabilities while also providing high agility, as each app component may be developed independently of the others.
15. What do you understand by Domain-Driven Design?
It is an architectural style based on the concepts and principles of Object-Oriented Analysis Design. It is used to create a complicated system by linking the software system's relevant components into a constantly changing system. Three principles underpin domain-driven design:
Concentrate on the domain's core domain and domain logic.
Complex designs should be based on domain models.
Collaborate with domain experts to develop the application model and address any emergent domain-related challenges.
16. Difference between Cohesion and Coupling?
Coupling refers to the connection between module A and module B. Any module can be highly connected (very dependent), lightly coupled, or uncoupled with other modules. Loose coupling obtained through interfaces is the best coupling.
Cohesion is the connection between two or more pieces of a module. When a module has strong cohesiveness, it means it can complete a task as efficiently as possible without the need for communication with other modules. A module's functional strength is enhanced by high cohesiveness.
17. Mention the problems that Spring Cloud solves?
Spring cloud is capable of resolving the following issues:
There are network challenges, latency overhead, bandwidth issues, security issues, and other issues with distributed systems.
Issues with redundancy that arise in distributed systems.
Balancing the load distribution across resources such as network links, CPUs, clusters, etc.
Operational overheads are causing performance difficulties.
Service discovery concerns must be addressed to enable effective communication across services in a cluster.
18. What are Client certificates?
A digital certificate used to perform authorized requests to a distant server is a client certificate.
19. Why are containers used in Microservices?
Containers are the most convenient and efficient way to manage microservice-based applications. It also aids in individual development and deployment. Docker also allows you to encapsulate your dependencies and their microservices in a container image. Microservices can use these elements without any further effort.
20. What is Distributed Transaction?
Two or more network hosts are involved in a distributed transaction. Transactions are managed by a transaction manager responsible for generating and executing transactions. When more than one peer is engaged in a transaction, the transaction managers of each peer communicate with one another through subordinate or superior connections.
Similarly, the resource manager is in charge of resources and works with the distributed transaction coordinator to ensure transaction atomicity and isolation.
Microservices Interview Questions for Experienced
21. What are Reactive Extensions in Microservices?
Rx stands for Reactive Extensions. It's a design pattern that lets you acquire data by calling different services and combining the results. Rx is a standard distributed system tool that works in the opposite direction of historical flows.
22. How do independent microservices communicate with each other?
It is dependent on the requirements of your project. On the other hand, developers typically employ HTTP/REST with JSON or Binary protocols. They can, however, communicate via any protocol.
23. What are the most significant advantages and disadvantages of using Microservices?
The following is a list of the essential benefits and drawbacks of using Microservices:
Advantages of Microservices
- Provide improved scalability
- Increased Agility
- Localized Complexity
- Provide fault isolation
- Debugging & Maintenance are easy and simplified.
- Communication between developers with business users is accessible and better.
- Smaller development teams
- You can easily upgrade the technology.
Disadvantages of Microservices
- It necessitates meticulous pre-planning before use.
- It employs difficult-to-calculate modular dependencies.
- Third-party programs are challenging to manage.
- It isn't easy to keep track of modular interdependencies.
- Malicious invasions will have more opportunities.
- End-to-end testing is a difficult task.
- Challenges in Deployment
Microservices MCQs
1. What is a microservice?
a) A small-scale application
b) A method of breaking down a monolithic application into smaller, independent services
c) A design pattern for data storage
d) An approach to secure a system
Answer: b) A method of breaking down a monolithic application into smaller, independent services
2. Which of the following is an advantage of using microservices?
a) Single point of failure
b) Better scalability
c) Slower development cycles
d) Tight coupling of services
Answer: b) Better scalability
3. In microservices architecture, each service should be:
a) Dependent on other services
b) Independently deployable
c) Monolithic in design
d) Managed centrally
Answer: b) Independently deployable
4. Which protocol is commonly used for communication between microservices?
a) FTP
b) HTTP/HTTPS
c) POP3
d) SMTP
Answer: b) HTTP/HTTPS
5. What is the role of an API Gateway in microservices?
a) It stores all the data for microservices
b) It handles service orchestration
c) It routes client requests to the appropriate microservice
d) It monitors the performance of microservices
Answer: c) It routes client requests to the appropriate microservice
6. Which tool is commonly used for container orchestration in microservices?
a) Docker
b) Kubernetes
c) Jenkins
d) Ansible
Answer: b) Kubernetes
7. In a microservices architecture, what is the benefit of using containers?
a) Increased memory usage
b) Faster development time
c) Improved portability and isolation
d) Centralized management
Answer: c) Improved portability and isolation
8. How do microservices typically communicate with each other?
a) Direct database access
b) Remote Procedure Calls (RPC)
c) RESTful APIs
d) Shared memory
Answer: c) RESTful APIs
9. Which of the following is a challenge when implementing microservices?
a) Easy to scale
b) Decentralized data management
c) Simpler debugging
d) High reliability
Answer: b) Decentralized data management
10. What is the purpose of service discovery in microservices?
a) To locate the database for a service
b) To find the IP addresses of services
c) To monitor the services' performance
d) To secure communication between services
Answer: b) To find the IP addresses of services
Frequently Asked Questions
Why Would You Opt for Microservices Architecture?
- Microservices are easily adaptable to different frameworks and technologies.
- The failure of a single process has no bearing on the rest of the system.
- Assists both large and small businesses.
- It can be deployed on its own and in a shorter amount of time.
Why Do People Hesitate to Use Microservices?
This is a question that I've seen many developers struggle with. After all, they'll be asked this question during a job interview for a microservices architect, so recognizing the drawbacks can be difficult. Here are some excellent responses:
- They require heavy investment
- They need rich architecture set up
- They need excessive Planning for handling operations overhead
- They have autonomous staff selection
What are the main differences between Microservices and Monolithic Architecture?
Microservices architecture is loosely coupled, whereas monolithic architecture is firmly tied. Microservices are more concerned with products than projects, whereas Monolithic is the opposite. The microservice architecture allows for faster service launch than monolithic architecture. Any modifications made to a single data model in a microservice architecture have no impact on other microservices. However, in a monolithic architecture, any changes to the data model affect the entire database.
Conclusion
This article covers the key microservices interview questions. We hope it has enhanced your understanding of these important topics. The answers are concise and direct, helping you prepare effectively for microservices interviews.
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