Top 50 Microservices Interview Questions for Freshers and Experienced

According to Gartner, microservices are the new application platform for cloud development. Microservices are deployed and managed independently, and once implemented inside containers they have very little interaction with the underlying OS. So, if you are planning to start your career in the Microservices and you wish to know the skills related to it, now is the right time to dive in, when the technology is in its nascent state. Hence, to help you prepare for your interviews, I have come up with Microservices Interview Questions and Answers blog.

In this Microservices interview questions blog, I have collected the most frequently asked questions by interviewers. These questions are collected after consulting with experts.

In case you have attended any Microservices interview in the recent past, do paste those interview questions in the comments section and we’ll answer them ASAP. You can also comment below if you have any questions in your mind, which you might face in your Microservices interview.

Top Microservices Interview Questions 

1. List down the advantages of Microservices Architecture.
2. What do you know about Microservices?
3. What are the features of Microservices?
4. What are the best practices to design Microservices?
5. How does Microservice Architecture work?
6. What are the pros and cons of Microservice Architecture?
7. What is the difference between Monolithic, SOA and Microservices Architecture?
8. What are the challenges you face while working Microservice Architectures?
9. What are the key differences between SOA and Microservices Architecture?
10. What are the characteristics of Microservices?

Q1. List down the advantages of Microservices Architecture.

Q2. What do you know about Microservices?

• Microservices, aka Microservice Architecture, is an architectural style that structures an application as a collection of small autonomous services, modeled around a business domain.
• In layman terms, you must have seen how bees build their honeycomb by aligning hexagonal wax cells.
• They initially start with a small section using various materials and continue to build a large beehive out of it.
• These cells form a pattern resulting in a strong structure which holds together a particular section of the beehive.
• Here, each cell is independent of the other but it is also correlated with the other cells.
• This means that damage to one cell does not damage the other cells, so, bees can reconstruct these cells without impacting the complete beehive.

Fig 1: Beehive Representation of Microservices 

Refer to the above diagram. Here, each hexagonal shape represents an individual service component. Similar to the working of bees, each agile team builds an individual service component with the available frameworks and the chosen technology stack. Just as in a beehive, each service component forms a strong microservice architecture to provide better scalability. Also, issues with each service component can be handled individually by the agile team with no or minimal impact on the entire application.

Q3. What are the features of Microservices?

Fig 3: Features of Microservices 

• Decoupling – Services within a system are largely decoupled. So the application as a whole can be easily built, altered, and scaled
• Componentization – Microservices are treated as independent components that can be easily replaced and upgraded
• Business Capabilities – Microservices are very simple and focus on a single capability
• Autonomy – Developers and teams can work independently of each other, thus increasing speed
• Continous Delivery – Allows frequent releases of software, through systematic automation of software creation, testing, and approval
• Responsibility – Microservices do not focus on applications as projects. Instead, they treat applications as products for which they are responsible
• Decentralized Governance – The focus is on using the right tool for the right job. That means there is no standardized pattern or any technology pattern. Developers have the freedom to choose the best useful tools to solve their problems
• Agility – Microservices support agile development. Any new feature can be quickly developed and discarded again

Q4. What are the best practices to design Microservices?

The following are the best practices to design microservices:

Fig 4: Best Practices to Design Microservices  

Q5. How does Microservice Architecture work?

A microservice architecture has the following components:

Fig 5: Architecture of Microservices

• Clients – Different users from various devices send requests.
• Identity Providers – Authenticates user or clients identities and issues security tokens.
• API Gateway – Handles client requests.
• Static Content – Houses all the content of the system.
• Management –  Balances services on nodes and identifies failures.
• Service Discovery – A guide to find the route of communication between microservices.
• Content Delivery Networks – Distributed network of proxy servers and their data centers.
• Remote Service – Enables the remote access information that resides on a network of IT devices.

Q6. What are the pros and cons of Microservice Architecture?

Q7. What is the difference between Monolithic, SOA and Microservices Architecture?

Fig 6: Comparison Between Monolithic SOA & Microservices 

• Monolithic Architecture is similar to a big container wherein all the software components of an application are assembled together and tightly packaged.
• A Service-Oriented Architecture is a collection of services which communicate with each other. The communication can involve either simple data passing or it could involve two or more services coordinating some activity.
• Microservice Architecture is an architectural style that structures an application as a collection of small autonomous services, modeled around a business domain.

Q8. What are the challenges you face while working Microservice Architectures?

Developing a number of smaller microservices sounds easy, but the challenges often faced while developing them are as follows.

• Automate the Components: Difficult to automate because there are a number of smaller components. So for each component, we have to follow the stages of  Build, Deploy and, Monitor.
• Perceptibility: Maintaining a large number of components together becomes difficult to deploy, maintain, monitor and identify problems. It requires great perceptibility around all the components.
• Configuration Management: Maintaining the configurations for the components across the various environments becomes tough sometimes.
• Debugging: Difficult to find out each and every service for an error. It is essential to maintain centralized logging and dashboards to debug problems.

Q9. What are the key differences between SOA and Microservices Architecture?

The key differences between SOA and microservices are as follows:

Q10. What are the characteristics of Microservices?

You can list down the characteristics of microservices as follows:

Fig 7: Characteristics of Microservices

You may go through this recording of Microservices Interview Questions and Answers where our instructor has explained the topics in a detailed manner with examples that will help you to understand this concept better.

Q11. Name three commonly used tools for Microservices

 The three commonly used tools for Microservices are:

Docker: Docker is a tool that lets developers set up apps in lightweight, portable containers in an automated way. It helps put the microservices and their dependencies into containers. This makes sure that the microservices are the same in all environments and makes it easier to launch and grow them.

Kubernetes: Kubernetes is a powerful tool for managing, scaling, and automating the launch of Docker containers. It does this by orchestrating how containers work together. It has important tools for running microservices in a live setting, such as load balancing, service discovery, self-healing, and automatic scaling.

Spring Boot: Spring Boot is a famous platform built on Java that makes it easier to build and launch microservices. It has features like built-in web servers, auto-configuration, and measures that are ready for production, which make it easier for developers to build, test, and launch microservices.

Q12. What is Monolithic Architecture?

Monolithic architecture is a traditional way of making software, in which all of an application’s parts and functions are tightly tied together and packaged as a single unit. In a monolithic program, the user interface, business logic, and data access layer all live in the same codebase and are delivered as a single unit. In the early days of software creation, this method was often used.

Key characteristics of a Monolithic Architecture:

1. Single Codebase: The entire application is developed and maintained within a single code repository.
2. Tight Coupling : Components and modules within the application are tightly interconnected, making it difficult to modify or replace individual parts without impacting the entire system.
3. Scalability Challenges : Scaling a monolithic application can be challenging as all components need to be scaled together, even if only a specific part requires more resources.
4. Monolithic Deployment : The application is deployed as a whole, which can lead to longer deployment cycles and increased downtime during updates.
5. Technology Stack : Monolithic applications often use a uniform technology stack for the entire system.
6. Development and Testing : The development and testing of monolithic applications can become complex and time-consuming as the codebase grows.
7. Failure Impact : A failure in one component can potentially bring down the entire application.

Even though monolithic design has some problems, it has been used successfully for many years, especially for smaller applications and projects that aren’t too big or complicated. But as applications get bigger and more complicated and as the need for faster development processes and better scalability grows, monolithic design can become limited. This led to the rise of microservices design, in which systems are broken up into smaller, loosely connected services that can be built, deployed, and scaled separately.

Q13. In a Microservices setting, how useful are reports and dashboards?

In a Microservices setting, reports and dashboards are incredibly useful and often vital for the effective operation and management of the distributed system. Here are some reasons why reports and dashboards are essential in a Microservices environment:

1. Visibility into Microservices : Microservices design can be made up of many different services, each of which is responsible for a different set of functions. Reports and dashboards give a consolidated view of these services, making it easier for devs, management teams, and users to track and understand the health and performance of the system as a whole.
2. Service Monitoring and Debugging : Reports and graphs let you keep an eye on the response times, mistake rates, and resource usage of each microservice in real time. This makes it easier to find speed problems, bottlenecks, and errors in individual services and fix them quickly.
3. End-to-End System Performance : Dashboards show how a program works as a whole, including how the microservices work together. This end-to-end view makes it easier to find problems caused by exchanges between services and makes sure that services work well together.
4. Scalability and Resource Management :Monitoring how each microservice uses its resources helps with capacity planning and making the best use of resources. Reports and tools help teams find services that need more resources and change them so they can handle more traffic.
5. Alerting and Incident Response : Dashboards can be set up to send alerts based on predetermined limits, which makes it possible to respond to incidents in a timely manner. Teams can get alerts in real time, which lets them act right away when important events or service breakdowns happen.
6. Versioning and Deployment Analysis : When updates or changes are made to microservices, reports and graphs can help compare how well the different versions of the service work. This lets teams figure out how changes will affect things and make sure deployments go smoothly and work well.
7. Business Metrics and Decision Making : Metrics that are important to a business, like user interaction, sales, and conversion rates, can be shown in reports and screens. These insights help stakeholders make choices based on data, understand how microservices affect business performance, and decide which changes to make first.
8. Security and Compliance Monitoring : Centralizing security logs and data in reports and dashboards makes it easier to find and deal with possible security risks and make sure that security policies are being followed.
9. User Behavior Analysis : Analyzing user interactions with various microservices gives significant information into user behavior and preferences. This knowledge helps improve the user experience and make services fit the wants of the user.

Overall, reports and dashboards are very important in a Microservices setting because they provide clarity, track system success, and make it easier to make good decisions. They make it easier to see what’s going on and let teams react to problems before they happen. This makes microservices-based apps more stable, scalable, and reliable.

Q14.Tell me the name of some famous companies which are using Microservice architecture.

There are  several famous companies that have adopted the Microservices architecture to build their applications and services. Some of these companies include:

1. Netflix : Netflix is a well-known entertainment streaming platform that heavily relies on Microservices architecture. It uses hundreds of individual microservices to handle different aspects of its platform, such as user authentication, content recommendation, and video streaming.
2. Amazon : Amazon, one of the largest e-commerce and cloud computing companies in the world, has adopted a Microservices approach for various services, including Amazon Prime, AWS (Amazon Web Services), and other online retail functionalities.
3. Uber : Uber, the popular ride-hailing service, employs Microservices architecture to manage its vast and complex operations, which include real-time location tracking, ride dispatching, payment processing, and more.
4. Twitter : Twitter, the social media platform, has shifted to a Microservices architecture to handle its millions of users, tweets, and real-time interactions efficiently.
5. Spotify : Spotify, the music streaming service, employs Microservices architecture to manage its vast music library, user preferences, and personalized playlists.
6. Google : Google, the multinational technology company, uses Microservices for various products and services, including Google Search, Gmail, and Google Maps.
7. LinkedIn : LinkedIn, the professional networking platform, utilizes Microservices architecture to manage user profiles, job listings, and networking features.
8. eBay : eBay, the popular online marketplace, has adopted Microservices architecture to handle its extensive product catalog, user accounts, and payment processing.
9. PayPal : PayPal, the digital payment platform, uses Microservices to manage transactions, user accounts, and security features.
10. Airbnb : Airbnb, the online hospitality service, employs Microservices to handle booking management, search functionality, and user reviews.

It’s important to remember that a company’s use of Microservices design can change, and some parts of their systems may still be built with other methods. Also, the technology world is always changing, so new companies may have started using Microservices design since the last time I wrote about it.

Microservices Interview Questions for Experienced

Q11. What is Domain Driven Design?

Fig 8: Principles of DDD – Microservices Interview Questions 

Q12. Why there is a need for Domain Driven Design (DDD)?

Fig 9: Factors Why we need DDD

Q13. What is Ubiquitous language?

If you have to define the Ubiquitous Language (UL), then it is a common language used by developers and users of a specific domain through which the domain can be explained easily.

The ubiquitous language has to be crystal clear so that it brings all the team members on the same page and also translates in such a way that a machine can understand.

Q14. What is Cohesion?

The degree to which the elements inside a module belong together is said to be cohesion.

Q15.  What is Coupling?

The measure of the strength of the dependencies between components is said to be coupling. A good design is always said to have High Cohesion and Low Coupling.

Q16.  What is REST/RESTful and what are its uses?

Representational State Transfer (REST)/RESTful web services are an architectural style to help computer systems communicate over the internet. This makes microservices easier to understand and implement.

Microservices can be implemented with or without RESTful APIs, but it’s always easier to build loosely coupled microservices using RESTful APIs.

Q17. What do you know about Spring Boot?

It’s a knows fact that spring has become more and more complex as new functionalities have been added. If you have to start a new spring project, then you have to add build path or add maven dependencies, configure application server, add spring configuration. So everything has to be done from scratch.

Spring Boot is the solution to this problem. Using spring boot you can avoid all the boilerplate code and configurations. So basically consider yourself as if you’re baking a cake spring is like the ingredients that are required to make the cake and spring boot is the complete cake in your hand.

Fig 10: Factors of Spring Boot 

Q18. What is an actuator in Spring boot?

Spring Boot actuator provides restful web services to access the current state of running an application in the production environment. With the help of actuator, you can check various metrics and monitor your application.

Q19. What is Spring Cloud?

According to the official website of Spring Cloud, Spring Cloud provides tools for developers to quickly build some of the common patterns in distributed systems (e.g. configuration management, service discovery, circuit breakers, intelligent routing, leadership election, distributed sessions, cluster state).

Q20. What problems are solved by Spring Cloud?

While developing distributed microservices with Spring Boot we face few issues which are solved by Spring Cloud.

• The complexity associated with distributed systems – This includes network issues, Latency overhead, Bandwidth issues, security issues.
• Ability to handle Service Discovery – Service discovery allows processes and services in a cluster to find each other and communicate.
• Solved redundancy issues – Redundancy issues often occur in distributed systems.
• Load balancing – Improves the distribution of workloads across multiple computing resources, such as a computer cluster, network links, central processing units.
• Reduces performance issues – Reduces performance issues due to various operational overheads.

Q21.  What is the use of WebMvcTest annotation in Spring MVC applications?

WebMvcTest annotation is used for unit testing Spring MVC Applications in cases where the test objective is to just focus on Spring MVC Components. In the snapshot shown above, we want to launch only the ToTestController. All other controllers and mappings will not be launched when this unit test is executed.

Q22. Can you give a gist about Rest and Microservices?

REST

Though you can implement microservices in multiple ways, REST over HTTP is a way to implement Microservices. REST is also used in other applications such as web apps, API design, and MVC applications to serve business data.

Microservices

Microservices is an architecture wherein all the components of the system are put into individual components, which can be built, deployed, and scaled individually. There are certain principles and best practices of Microservices that help in building a resilient application.

In a nutshell, you can say that REST is a medium to build Microservices.

Q23. What are different types of Tests for Microservices?

While working with microservices, testing becomes quite complex as there are multiple microservices working together. So, tests are divided into different levels.

• At the bottom level, we have technology-facing tests like- unit tests and performance tests. These are completely automated.
• At the middle level, we have tests for exploratory testing like the stress tests and usability tests.
• At the top level, we have acceptance tests that are few in number. These acceptance tests help stakeholders in understanding and verifying software features.

Q24. What do you understand by Distributed Transaction?

Distributed Transaction is any situation where a single event results in the mutation of two or more separate sources of data which cannot be committed atomically. In the world of microservices, it becomes even more complex as each service is a unit of work and most of the time multiple services have to work together to make a business successful.

Q25. What is an Idempotence and where it is used?

Idempotence is the property of being able to do something twice in such a way that the end result will remain the same i.e. as if it had been done once only.

Usage: Idempotence is used at the remote service, or data source so that, when it receives the instruction more than once, it only processes the instruction once.

Q26. What is Bounded Context?

Bounded Context is a central pattern in Domain-Driven Design. It is the focus of DDD’s strategic design section which is all about dealing with large models and teams. DDD deals with large models by dividing them into different Bounded Contexts and being explicit about their inter-relationships.

Q27. What is Two Factor Authentication?

Two-factor authentication enables the second level of authentication to an account log-in process.

Fig11: Representation of Two Factor Authentication

So suppose a user has to enter only username and password, then that’s considered a single-factor authentication.

Q28. What are the types of credentials of Two Factor Authentication?

The three types of credentials are:

Fig 12: Types of Credentials of Two Factor Authentication 

Q29. What are Client certificates?

A type of digital certificate that is used by client systems to make authenticated requests to a remote server is known as the client certificate. Client certificates play a very important role in many mutual authentication designs, providing strong assurances of a requester’s identity.

Q30. What is the use of PACT in Microservices architecture?

PACT is an open source tool to allow testing interactions between service providers and consumers in isolation against the contract made so that the reliability of Microservices integration increases.

Usage in Microservices:

• Used to implement Consumer Driven Contract in Microservices.
• Tests the consumer-driven contracts between consumer and provider of a Microservice.

Q31. What is OAuth?

OAuth stands for open authorization protocol. This allows accessing the resources of the resource owner by enabling the client applications on HTTP services such as third-party providers Facebook, GitHub, etc. So with this, you can share resources stored on one site with another site without using their credentials.

Q32. What is Conway’s law?

“Any organization that designs a system (defined broadly) will produce a design whose structure is a copy of the organization’s communication structure.” – Mel Conway

Fig 13: Representation of Conway’s Law – Microservices Interview Questions 

This law basically tries to convey the fact that, in order for a software module to function, the complete team should communicate well. Therefore the structure of a system reflects the social boundaries of the organization(s) that produced it.

Q33. What do you understand by Contract Testing?

According to Martin Flower, contract test is a test at the boundary of an external service which verifies that it meets the contract expected by a consuming service.

Also, contract testing does not test the behavior of the service in depth. Rather, it tests that the inputs & outputs of service calls contain required attributes and the response latency, throughput is within allowed limits.

Q34. What is End to End Microservices Testing?

End-to-end testing validates each and every process in the workflow is functioning properly. This ensures that the system works together as a whole and satisfies all requirements.

In layman terms, you can say that end to end testing is a kind of tests where everything is tested after a particular period.

Fig 14: Hierarchy of Tests – Microservices Interview Questions 

Q35. What is the use of Container in Microservices?

Containers are a good way to manage microservice based application to develop and deploy them individually. You can encapsulate your microservice in a container image along with its dependencies, which then can be used to roll on-demand instances of microservice without any additional efforts required.

Fig 15: Representation of Containers and How they are used in Microservices – Microservices Interview Questions 

Q36. What is DRY in Microservices architecture?

DRY stands for Don’t Repeat Yourself. It basically promotes the concept of reusing the code. This results in developing and sharing the libraries which in turn result in tight coupling.

Q37. What is a Consumer-Driven Contract (CDC)?

This is basically a pattern for developing Microservices so that they can be used by external systems. When we work on microservices, there is a particular provider who builds it and there are one or more consumers who use Microservice.

Generally, providers specify the interfaces in an XML document. But in Consumer Driven Contract, each consumer of service conveys the interface expected from the Provider.

Q38. What is the role of Web, RESTful APIs in Microservices?

A microservice architecture is based on a concept wherein all its services should be able to interact with each other to build a business functionality. So, to achieve this, each microservice must have an interface. This makes the web API a very important enabler of microservices. Being based on the open networking principles of the Web, RESTful APIs provide the most logical model for building interfaces between the various components of a microservice architecture.

Q39. What do you understand by Semantic monitoring in Microservices architecture?

Semantic monitoring, also known as synthetic monitoring combines automated tests with monitoring the application in order to detect business failing factors.

Q40. How can we perform Cross-Functional testing?

Cross-functional testing is a verification of non-functional requirements, i.e. those requirements which cannot be implemented like a normal feature.

Q41. How can we eradicate non-determinism in tests?

Non-Deterministic Tests (NDT)  are basically unreliable tests.  So, sometimes it may happen that they pass and obviously sometimes they may also fail. As and when they fail, they are made to re-run to pass.

Some ways to remove non-determinism from tests are as follows:

1. Quarantine
2. Asynchronous
3. Remote Services
4. Isolation
5. Time
6. Resource leaks

Q42. What is the difference between Mock or Stub?

Stub

• A dummy object that helps in running the test.
• Provides fixed behavior under certain conditions which can be hard-coded.
• Any other behavior of the stub is never tested.

For example, for an empty stack, you can create a stub that just returns true for empty() method. So, this does not care whether there is an element in the stack or not.

Mock

• A dummy object in which certain properties are set initially.
• The behavior of this object depends on the set properties.
• The object’s behavior can also be tested.

For example, for a Customer object, you can mock it by setting name and age. You can set age as 12 and then test for isAdult() method that will return true for age greater than 18. So, your Mock Customer object works for the specified condition.

Q43. What do you know about Mike Cohn’s Test Pyramid?

Mike Cohn provided a model called Test Pyramid. This describes the kind of automated tests required for software development.

Fig 16: Mike Cohn’s Test Pyramid – Microservices Interview Questions

As per pyramid, the number of tests at first layer should be highest. At service layer, the number of tests should be less than at the unit test level, but more than at the end-to-end level.

Q44. What is the purpose of Docker?

Docker provides a container environment that can be used to host any application. In this, the software application and the dependencies which support it are tightly-packaged together.

So, this packaged product is called a Container and since it is done by Docker, it is called Docker container!

Q45. What is Canary Releasing?

Canary Releasing is a technique to reduce the risk of introducing a new software version in production. This is done by slowly rolling out the change to a small subset of users before giving it out to the entire infrastructure, i.e. making it available to everybody.

Q46. What do you mean by Continuous Integration (CI)?

Continuous Integration (CI) is the process of automating the build and testing of code every time a team member commits changes to version control. This encourages developers to share code and unit tests by merging the changes into a shared version control repository after every small task completion.

Q47. What is Continuous Monitoring?

Continuous monitoring gets into the depth of monitoring coverage, from in-browser front-end performance metrics, through application performance, and down to host virtualized infrastructure metrics.

Q48. What is the role of an architect in Microservices architecture?

An architect in microservices architecture plays the following roles:

• Decides broad strokes about the layout of the overall software system.
• Helps in deciding the zoning of the components. So, they make sure components are mutually cohesive, but not tightly coupled.
• Code with developers and learn the challenges faced in day-to-day life.
• Make recommendations for certain tools and technologies to the team developing microservices.
• Provide technical governance so that the teams in their technical development follow principles of Microservice.

Q49. Can we create State Machines out of Microservices?

As we know that each Microservice owning its own database is an independently deployable program unit, this, in turn, lets us create a State Machine out of it. So, we can specify different states and events for a particular microservice.

For Example, we can define an Order microservice. An Order can have different states. The transitions of Order states can be independent events in the Order microservice.

Q50. What are Reactive Extensions in Microservices?

Reactive Extensions also are known as Rx. It is a design approach in which we collect results by calling multiple services and then compile a combined response. These calls can be synchronous or asynchronous, blocking or non-blocking. Rx is a very popular tool in distributed systems which works opposite to legacy flows.

Q55. Explain the term Eureka in Microservices.

Eureka is a key component of microservice architecture because it makes it easy to scale and manage microservices. Without Eureka, each microservice would need to know the location of all the other microservices it needs to communicate with. This would make it difficult to scale microservices because you would need to update the configuration of each microservice whenever you added or removed a microservice.

Eureka also makes it easy to failover to a different microservice if one fails. When a microservice registers with Eureka, it provides a list of other microservices that it depends on. If the microservice fails, Eureka will remove it from the registry, and other microservices will be notified. The other microservices can then failover to a different microservice that provides the same functionality.

To call microservices from the Eureka server, you can use the Eureka client library. The Eureka client library will query the Eureka registry to find the location of the microservice you want to call. Once it has the location of the microservice, it will make a call to the microservice.

Here are some of the benefits of using Eureka in microservices:

• Easy scalability: Eureka makes it easy to scale microservices because you don’t need to update the configuration of each microservice when you add or remove a microservice.
• Fault tolerance: Eureka makes it easy to failover to a different microservice if one microservice fails.
• Centralized management: Eureka provides a centralized way to manage microservices. You can use Eureka to view the status of all your microservices and manage their configuration.

Q56. Explain the way to implement service discovery in a microservices architecture.

Implementing service discovery in a Microservices architecture involves setting up a service registry and configuring individual Microservices to register themselves with the registry. Clients can then query the service registry to discover the locations of the services they need to communicate with. Here’s a step-by-step guide to implementing service discovery in a Microservices environment:

1. Choose a Service Registry: Select a service registry tool that fits your technology stack and requirements. Some popular service registry options are Eureka (by Netflix), Consul, etc., and ZooKeeper. Each has its strengths and features, so choose the one that best suits your needs.
2. Set Up the Service Registry: Install and configure the chosen service registry tool. In a distributed Microservices architecture, it’s good practice to set up multiple instances of the service registry for redundancy and fault tolerance.
3. Service Registration: In each Microservice, add code to register with the service registry when it starts up. This registration process typically involves sending essential metadata such as the service name, instance ID, host, port, and health status to the service registry.
4. Health Checks: Implement health checks in each Microservice. Periodically, the Microservice sends heartbeats or health check status to the service registry to indicate its availability and health. If a service fails health checks, it is automatically removed from the registry.
5. Service Discovery: Clients that need to interact with specific Microservices will query the service registry for the locations of those services. The service registry responds with the available instances of the requested service, along with their metadata.
6. Load Balancing (Optional): To achieve better performance and resource utilization, clients can use load balancing strategies when interacting with Microservices. They can distribute incoming requests across available instances of the service retrieved from the service registry.
7. Client-Side Discovery and Circuit Breakers: Implement client-side discovery to allow the clients to handle service location and load balancing themselves. Additionally, consider using circuit breakers to prevent cascading failures when interacting with services.
8. Resilience and High Availability: For high availability and fault tolerance, deploy multiple instances of the service registry and use a peer-to-peer communication model. This ensures that even if some instances fail, others can continue serving requests.
9. Monitoring and Alerting: Implement monitoring and alerting for the service registry and Microservices. Monitor the health of service instances and the registry itself, and set up alerts for any anomalies or failures.

By putting service discovery in place in a Microservices design, you make it possible for services to talk to each other in a dynamic and seamless way. This promotes loose coupling and scaling. Service discovery makes it easier to launch, scale, and handle Microservices. This means that the system can adapt to changes in the service landscape without having to be manually reconfigured or have service endpoints hardcoded.

Q57. What are the 3 C’s of microservices?

The “Three C’s” of Microservices refer to three essential principles or characteristics that are often associated with Microservices architecture. These principles help guide the design and development of Microservices-based applications to ensure their effectiveness and success. The Three C’s are:

1. Componentization: This concept says that a monolithic program should be broken up into smaller parts, called Microservices, that can be deployed and managed on their own. Each Microservice is in charge of a certain business capability or function, which gives teams the freedom to build, test, and launch them on their own. Componentization encourages a modular and independent architecture, which makes the program easier to manage and grow.
2. Communication: In a Microservices design, it’s important for services to talk to each other so that the whole system works well. Services talk to each other through well-defined APIs, which often use lightweight protocols like HTTP/REST or message systems like Kafka or RabbitMQ. Communication patterns must be designed in a way that allows free linking and flexibility, so that services can change on their own without affecting the whole system.
3. Containerization: Containerization is the process of putting apps and the things they need into separate containers, like Docker containers. Containers provide a consistent and portable setting that makes sure Microservices run the same way on different devices and environments. Containerization makes it easy to launch, scale, and handle Microservices. For this reason, it is a core part of many Microservices architectures.

These Three C’s—Componentization, Communication, and Containerization—help organizations adopt a Microservices architecture successfully. They promote flexibility, scalability, and maintainability, allowing development teams to build complex and distributed applications that can evolve and adapt to changing business needs efficiently.

Q58. Explain Microservices in layman terms.

Microservices is an architectural approach where a large application is divided into small, independent services that communicate with each other, enabling flexibility, scalability, and faster development.

Imagine you have a big and complex task to accomplish, like building a huge LEGO castle. In the traditional way (like a monolithic approach), you would try to put all the LEGO pieces together in one giant structure, making it difficult to manage and modify.

Now, think of Microservices like building smaller, separate LEGO sections, each with its specific purpose (like a tower, a wall, a bridge, etc.). Each of these sections can be built and managed independently. When you need to change or add something, you can focus on that specific section without affecting the rest of the castle.

In the same way, Microservices in software are like building a big application as a collection of smaller, independent pieces or services. Each service has its job to do, like handling user authentication, processing payments, or showing product recommendations. These services can be developed, updated, and scaled separately, making it easier to work on the application and respond to changes faster.

With Microservices, teams can work on different parts of the application simultaneously, just like different LEGO builders working on their specific sections of the castle. This approach helps make the application more flexible, scalable, and easier to maintain.

So, Microservices is like assembling a complex application by breaking it down into smaller, manageable pieces, where each piece is responsible for a specific task, and they all work together to create a powerful and adaptable system.

Hope these Microservices Interview Questions would help you in your Microservices Architect Interviews.

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