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Microservices Questions and Answers

Updated: Jan 14, 2023

This tutorial will show you the best Microservice Interview Question and Answers.



Microservices improve performance because teams handle specific services rather than an app as a whole. This advantage leads to greater accountability, compliance, and data security. Microservices allow developers to become language and technology agnostic.


Below are some of the best Microservice Question and Answers:


Q 1: What are Microservices?

Microservices, also known as Microservices Architecture, is basically an SDLC approach in which large applications are built as a collection of small functional modules. It is one of the most widely adopted architectural concepts within software development. In addition to helping in easy maintenance, this architecture also makes development faster. Additionally, microservices are also a big asset for the latest methods of software development such as DevOps and Agile. Furthermore, it helps deliver large, complex applications promptly, frequently, and reliably.


Q 2: What are the Advantages of Microservices?

  • Self-contained, and independent deployment module.

  • Independently managed services.

  • In order to improve performance, the demand service can be deployed on multiple servers.

  • It is easier to test and has fewer dependencies.

  • A greater degree of scalability and agility.

  • Simplicity in debugging & maintenance.

  • Better communication between developers and business users.

  • Development teams of a smaller size


Q 3: What are the Disadvantages of Microservices?

  • Due to the complexity of the architecture, testing and monitoring are more difficult.

  • Lacks the proper corporate culture for it to work.

  • Pre-planning is essential.

  • Complex development.

  • Requires a cultural shift.

  • Expensive compared to monoliths.

  • Security implications.

  • Maintaining the network is more difficult


Q 4: What are the challenges faced while using Microservices?

The challenges that one has to face while using microservices can be both functional and technical as given below:

  1. Require heavy infrastructure setup.

  2. Need Heavy investment.

  3. Require excessive planning to handle or manage operations overhead.

  4. Microservices are always interdependent. Therefore, they must communicate with each other.

  5. It is a heavily involved model because it is a distributed system.

  6. You need to be prepared for operations overhead if you are using Microservice architecture.

  7. To support heterogeneously distributed microservices, you need skilled professionals.

  8. It is difficult to automate because of the number of smaller components. For that reason, each component must be built, deployed, and monitored separately.

  9. It is difficult to manage configurations across different environments for all components.

  10. Challenges associated with deployment, debugging, and testing


Q 5: What is Microservice Architecture?

Microservices architecture (often shortened to microservices) refers to an architectural style for developing applications. Microservices allow a large application to be separated into smaller independent parts, with each part having its own realm of responsibility. To serve a single user request, a microservices-based application can call on many internal microservices to compose its response.


Q 6: How does Microservice Architecture works?

The Microservice architecture of an application can be simplified into multiple modules that independently perform the single precise standalone task. Let's see how Microservice architecture works:

  • An application is fragmented into loosely coupled various modules, each of which performs a distinct function.

  • It is distributed across clouds and data centers.

  • Each application module is an independent service/process that can be replaced, updated, or deleted without disrupting the rest of the application.

  • Under microservice architecture, an application can grow along with its requirements.


Q 7: What are the Tools used for Microservices?

There are three common tools used for Microservices, are:

  1. Docker

  2. Hystrix

  3. Wiremock


Q 8: Which companies are using Microservice Architecture?

Microservice Architecture is used by large-scale websites like:

  1. Netflix

  2. Amazon

  3. Twitter

  4. Uber

  5. Coca-Cola

  6. eBay

  7. Etsy


Q 9: What are the different types of Tests for Microservices?

In Microservice architecture tests are divided into three broad categories:

  • Bottom Level Test: The bottom-level tests perform general tests such as performance tests and unit tests. These kinds of tests are entirely automated.

  • Middle-Level Tests: The middle-level tests are used to perform exploratory tests such as the stress test and usability test.

  • Top Level Tests: The top-level tests are used to conduct acceptance tests, mostly fewer in numbers. These types of tests make stakeholders know about different software features.


Q 10: Explain Spring Cloud and Spring Boot.

Spring Cloud: Spring cloud is used for centralizing the configuration management and involves great security and integrity of Spring boot applications.


Spring Boot: Spring boot is defined as an open-source Java-based framework that is useful in creating microservices, based upon dependency spring cloud have multiple dependencies, and spring boot is a lightweight framework that has a less dependency, along with these differences between spring cloud and spring boots differ from each other in the field of Microservices, Features, Annotations, Advantages, Need, How they work, Components and applications.


Q 11: Explain the difference between Spring Cloud and Spring Boot.

SPRING CLOUD

SPRING BOOT

There is an open-source library for Spring Cloud

There is an open-source library for Spring Boot

This work well for managing configuration in it

This is labor that goes into creating services

A cloud-based application is a simple approach. So, they make many services available in one application. Spring Cloud is no different.

Spring Boot is useful for developing web applications. Hence, the apps are dependent on products. It is to cut the time spent on unit testing and integration testing.

Working : 1. Create a relational database and connect it to your application first.

2. Next, depending on that service, build an object in the data source class.

3. Further, spring Cloud has begun to function.

4. It stops the need for developers to access and create service connections.

Working: 1. The auto-configuration feature begins to function.

2. Based on the dependencies, it is an auto-setup as a Spring web app.

3. The classpath has these dependencies.

4. It then discovers classes with the aid of the classpath.

5. auto-configuration guarantees the creation of beans and wired for us.

Spring Cloud includes some important features available in this category: Service Discovery, Circuit Breakers, Routing and Messaging, Tracing, etc.

Spring Boot Initialize, Spring Boot Starter, SB Actuator, SB CLI, and so on.

Q 12: What issues are solved by Spring Clouds?

The following are the problems that can be solved with Spring Cloud:

  • Complicated issues caused by distributed systems: This includes network issues, latency problems, bandwidth problems, and security issues.

  • Service Discovery issues: Service discovery allows processes and services to communicate and locate each other within a cluster.

  • Redundancy issues: Distributed systems can often have redundancy issues.

  • Load balancing issues: Optimize the distribution of workloads among multiple computing resources, including computer clusters, central processing units, and network links.

  • Reduces performance issues: Reduces performance issues caused by various operational overheads.


Q 13:In which cases microservice architecture best suited?

Microservice architecture is best suited for desktop, web, mobile devices, Smart TVs, Wearable, etc.


Q 14: What is End-to-End Microservice testing?

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


Q 15: Define Containers in Microservices.

Containers are used for allocating and sharing resources. It is the most effective and easiest method for managing microservice-based applications to develop and deploy them individually. Using Docker, you may also encapsulate a microservice along with its dependencies in a container image, which can then be used to roll on-demand instances of the microservice without any additional work.


Q 16: What are the different strategies used in Microservice Deployment?

Following strategies are used in Microservices deployment:

  • Multiple Service Instance per Host: It is used to run single or multiple service instances of the application on a single or multiple physical/virtual hosts.

  • Service Instance per Host: It is used to run a service instance per host.

  • Service Instance per Container: It is used to run each service instance in its respective container.

  • Serverless Deployment: It packages the service as a ZIP file and uploads it to the Lambda function. The Lambda function is a stateless service that automatically runs enough micro-services to handle all requests.


Q 17: Explain the difference between SOA and Microservice Architecture.

SOA

Microservices

Services are reused and shared at the enterprise level

Services are decoupled and operate independently

Supports multiple message protocols such as Simple Object Access Protocol (SOAP), Advanced Messaging Queuing Protocol (AMQP) and Microsoft Messaging Queuing (MMQ)

Uses lightweight, language-agnostic messaging protocols such as HTTP, Representational State Transfers (REST) or Java Messaging Service (JMS)

Common data governance across the enterprise as a result of component sharing

No consistent data governance among teams due to the independent nature of services

Single data storage layer shared by all services within a given application

Independent data server or database for data storage for each service, as required


Q 18: Define Domain-Driven Design?

Domain-Driven Design is an architectural style based on Object-Oriented Analysis Design concepts and principles. It is used to develop a complex system by connecting the related components of the software system into a continuously evolving system. Domain-Driven Design is based on three principles:

  • Focus on the core domain and domain logic.

  • Base complex designs on models of the domain.

  • Collaborate with the domain experts to improve the application model and resolve any emerging domain-related issues regularly.


Q 19: Explain the difference between Coupling and Cohesion.

Coupling: Coupling is specified as a relationship between module A and another module B. There are mainly three types of coupling. Any module can be highly coupled (highly dependent), loosely coupled, and uncoupled with other modules. The best coupling is the loose coupling which can be achieved through interfaces.

Cohesion: Cohesion is the relationship between 2 or more parts within a module. The high cohesion within a module specifies that the module can perform a specific task with maximum efficiency on its own, without the need to communicate with other modules. High cohesion increases the functional strength of the module.


Q 20: How to implement Spring Security in Spring Boot Application?

We can quickly implement a Spring Security in a Spring Boot Application by using the following method:

  • By adding the spring-boot-starter-security in the file pom.xml

  • By creating a Spring config class that will override the required method while extending the WebSecurityConfigurerAdapter to achieve security in the application

Q 21: What is PACT in Microservices Architecture?

The contract between a consumer application and a provider application is known as a PACT. Each PACT is a collection of interactions. It is an open-source tool that can be used to implement the Consumer-Driven Contract in Microservices.


Q 22: What is the need for Reports and Dashboard in Microservices?

Reports and dashboards are mainly used to monitor microservices. There are multiple tools used for this purpose. Following is the list of some usages of Reports and dashboards in microservices:

  • Reports and dashboards are used to find out which microservices expose what resources.

  • It is also used to specify the services which are impacted whenever we make changes in a component.

  • It provides an easy point to access whenever documentation is required.

  • It specifies the versions of the components which are deployed.

  • It is also used to obtain a sense of maturity and compliance from the components.

Q 23: What do you understand by Tasklet in Microservices?

The Tasklet is a simple interface with a method to execute. We can use it to perform single tasks like running queries, deleting files, etc. In Spring Batch, the Tasklet is an interface used to perform unique tasks like clean or set up resources before or after any step execution.


Q 24: How can you balance the server-side load by utilizing Spring Cloud?

We can use the Netflix Zuul to balance the server-side load by utilizing Spring Cloud. It is also known as a JVM-based router.


Q 25: What is the use of Bounded Context in Domain-Driven Design?

The Bounded Context is a central pattern in Domain-Driven Design. It is the core of Domain-Driven Design's strategic design section, which deals with large models and teams. It is used to divide the large models into different Bounded Contexts and being explicit about their inter-relationships.



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