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Top 45 microservices questions and answers | What are microservices

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Microservices have emerged as the preferred application platform for developing cloud applications. According to a survey, almost 70% of enterprises are either adopting or considering microservices, with roughly 1/3 actually deploying them in production. A microservice is defined as follows by Gartner, a worldwide research and advising firm:

“a service-oriented application component that is tightly scoped, strongly encapsulated, loosely coupled, independently deployable and independently scalable”

This blog covers all you need to know if you’ve dealt with microservices before or if you haven’t. We’ll go through the top 40 microservices questions that people search. Let’s get started.

1. What are microservices really all about?

Microservices architecture is a sort of application infrastructure in which a program is made up of a collection of separately deployable services that may function on their own.

Because code may be altered in a single service without rewriting the entire system, such solutions are quicker to develop & easier to deploy. With such a mix of services, developers may create scalable apps with vast features.

There are several programming languages, frameworks, and tools available for developing microservices applications of varying scale and complexity. It is considerably easier to manage a small team of developers working on a collection of separate applications than it is to manage a big team producing a monolithic solution.

Microservices are essentially a collection of services that work together to run a whole application. APIs are used in this architecture to communicate information from one service to another, such as user requests or data streams.

2. What are a microservice architecture and its advantages?

The term “single responsibility principle” was coined by Robert C. Martin, and it implies that “assemble the things that change for the same reasons, and segregate the things that change for different reasons.”

This technique is taken by a microservices architecture, which expands it to loosely linked services that may be built, deployed, and maintained separately. Each of these services is in charge of a specific activity and may interface with other services via simple APIs to address a broader, more complicated business problem.

Software with a monolithic architecture at its heart is created as a single system. This massive codebase repository contains standardised software dev kits & components, making it more difficult to deploy and scale. Minor modifications would necessitate recreating the entire application. If you have a scalable app with multiple complex features, the monolithic approach might slow down the development cycle and cause a large codebase to suffer from various problems and vulnerabilities.

However, in the microservices architecture, each service is responsible for a certain task and communicates with one another via APIs. If one microservice fails, the remaining microservices remain operational and may be scaled separately.

Advantages of microservices architecture –

Because the component services are small, they may be constructed from the start by one or more workgroups separated by service limits, making it easy to scale up the development process if necessary.

Once established, individual services may be deployed separately of one another, making it simple to discover and scale active services independent of the entire application. Microservices also provide enhanced fault isolation, so that if one service fails, the entire programme does not cease to operate. When the problem is resolved, it is possible to deploy only the relevant service rather than redeploying the full application.

Another benefit of a microservices architecture is that it makes it simpler to select the technological stack (programming language, database, etc.) that is most suited for the desired functionality (service) rather of being forced to take a more standardised, one-size-fits-all approach.

3.   How Microservice Architecture Works

A microservice architecture has the following components –

  • Clients – Requests are sent by users from various devices.
  • Identity Providers – Verifies the identity of users or customers & issues security tokens.
  • API Gateway – Client queries are handled by the API Gateway.
  • Static Content — Contains all of the system’s content.
  • Management — Balances node services & detects problems.
  • Service Discovery — A tool for determining the best path for communication between microservices.
  • Content Delivery Networks (CDNs) – A network of proxy servers & data center that is distributed.
  • Remote Service – Allows remote access to information stored on a network of IT devices.

4. What are the Key Characteristics Of Microservices?

  • Essential messaging frameworks
  • Decentralized Governance
  • Easy Infrastructure automation
  • Design for failure
  • Infrastructure automation

5. What distinguishes Microservices from other types of software?

  • Frameworks for communicating that are essential
  • Governance is decentralized.
  • Infrastructure automation is simple.
  • Make a plan for failure.
  • Automation of infrastructure

6. What are the Pros and Cons of Microservices?

Pros –

  • The ability to employ many technologies.
  • Each microservice concentrates on a single capability.
  • Individually deployable units are supported.
  • Allow for regular software updates.
  • Each service’s security is ensured.
  • Multiple services are being developed and launched at the same time.

Cons –

  • Increases the difficulty of troubleshooting.
  • Delays are increased as a result of remote calls.
  • Increased configuration and other operations activities.
  • It is difficult to ensure transaction security.
  • It is difficult to track data across several borders.
  • It’s challenging to code between services.

7. Top 3 successful Examples of Microservices

  • Netflix
    Netflix was one of the first to use microservices and among the most talked about. They used AWS to set up the microservice architecture. Their transformation was prepared: first, they relocated movie encoding & other non-customer-facing apps. Then they detached customer-facing features such as account registration, movie selection, devices selection, as well as configuration. Netflix took 2 years to break its monolith into microservices, and in 2011 revealed the completion of its redesign and organization utilizing microservice architecture.
  • eBay
    eBay understood that in order to remain competitive, it needed to release quality features and improvements at a rapid pace. By dividing everything and using microservice architecture, eBay was able to respond to the emergent issues of the codebase’s expanding complexity, enhancing developer productivity and enabling a faster time-to-market while preserving site reliability. Similar to other microservices pioneers, eBay published open source solutions for the developer community while fixing their own issues.
  • Spotify
    Spotify was searching for a system that could expand to millions of users, support numerous platforms, and manage complicated business regulations by the time it had 75+ million active users monthly. They intended to be successful in a fast-paced market by reacting quickly and out-innovating the competition. Their technology teams met the aforementioned needs by establishing microservices managed by more than 90 autonomous full-stack teams grouped into tribes.

8. What is Monolithic Architecture?

Monolithic architecture is similar to a large container that contains all of an application’s software components in one package.

9. Why use microservices instead of monolithic systems?

There are several reasons to use microservices instead of a monolithic system. The main difference is the latter’s flexibility vs the former’s “rigidity.” Monolithicity’s downsides might present themselves in a number of ways. The following are the primary constraints associated with this architecture:

  • Because the program’s components are tightly connected, even little changes can have an influence on the total code; as a result, individual mistakes can interrupt the whole system, and even minor changes necessitate the reimplementation of the entire application.
  • A sizable monolithic application is hard to understand and “grasp,” which slows down alter implementation & increases the risk of errors; the effects of change are often difficult to predict, necessitating longer and more thorough testing.
  • A sizable monolithic application is hard to understand and “grasp,” which slows down alter implementation & increases the risk of errors; the effects of change are often difficult to predict, necessitating longer and more thorough testing.
  • Monolithic apps are more hard to scale, particularly when their individual components have conflicting requirements.
  • Individual components cannot be scaled; instead, the entire application must be scaled. The complex nature of a monolithic application makes it much more difficult to manage the system as the code base expands.
  • Similarly, it is more difficult to introduce new developers to work on monolith. This is particularly troublesome given that developers frequently switch companies and projects.

10. When are microservices a good choice” and “when are they not?

As a starting point, consider the following scenarios in which microservices are preferable over monolithic counterparts.

  • When you need scalability, agility, management, and delivery speed in your monolithic app.
  • When you need to rework historical apps in today’s programming languages or technical stacks to meet modern-day business needs.
  • Login services, search choices, authentication facilities, and other independent business apps or modules that must be employed across many channels are some other ideal examples.
  • If you’re creating a very agile application (product or service) which requires rapid delivery, innovation, and other features.

When not to use microservices –

Here are some points to keep in mind as a starting point.

  • Microservices are answers to complicated problems, and if your company doesn’t have any, you don’t have a framework in place to deal with the intricacies of microservices.
  • If you don’t have a large enough staff to accomplish the responsibilities, using microservices might have negative repercussions. This will simply cause delivery to be delayed.
  • Microservices might sometimes be a hindrance. You do not want this architecture if your application doesn’t need to be split down into microservices. There’s no requirement that all apps be split down into microservices. There are some which, by their very nature & functionality, are simple.

11. How to convert a monolithic application to microservices?

The following are typical steps in migrating from a monolithic system to a microservices-based system:

  • Determine the logical components.
  • Components should be flattened and refactored.
  • Determine component interdependencies.
  • Component groupings should be identified.
  • Create a remote user interface API.
  • Component groups should be migrated to macroservices (move component groups to separate projects and make separate deployments).
  • Macroservices should be converted to microservices.
  • Steps 6-7 should be repeated until all of the steps have been completed.

12. What is Spring Boot?

Spring Boot enables the rapid development of production-ready apps and includes the following non-functional features: Container-based embedded servers that are simple to deploy. It will aid in the monitoring of the various components. It also aids in the exterior configuration of components.

13. How to deploy microservices?

There are presently three major methods for deploying microservices:

  • Each Microservice instance should be deployed on its own Virtual Machine (e.g., AWS EC2 instance). A load balancer + automatic VM (un)provisioning services (typically employing a feedback control loop), such as AWS AutoScaling Groups (ASGs) with ASG rules triggered by CloudWatch alerts, can be used to scale each service horizontally.
  • Create a (Docker) container for each Microservice instance on Kubernetes (which provides load balancing, scaling, and other features).
  • Typically in conjunction with an API Gateway Service, deploy every Microservice as a Serverless Function, like AWS Lambda. This method requires the least amount of operational work and even claims “zero ops” (in lieu of DevOps). However, there is greater vendor lock-in and less flexibility over the processing environment.

14. How To Configure The Spring Boot Application Login?

The logging level of an application is commonly used to set the Spring Boot Application Login. The properties file is a text file that contains information about the It’s already set up as the console output.

15. How to test a microservice?

Microservices software tests ensure that microservices perform as expected in a fast and effective manner. The three primary methods to test microservices in the market are:

  • Functional testing – It is used to check the service’s business logic and behaviour. Because microservices lack a UI for straightforward testing, this is more difficult than testing in a typical monolithic design. The interface under test depicts a distant client that communicates through HTTP or another protocol.
  • Load testing – It is used to identify portions of an application that are not well-designed and may crash as a result of excessive visitor flow. Because each call to a microservice goes over the network, additional network activity might impact response times.
  • Resiliency testing – Used to see how the programme reacts to possible infrastructure breakdowns. For example, if a server providing a certain service is unavailable, crashes, or a portion of a network ceases transmitting data. In these circumstances, the developer should test the microservices app to see if it can continue to function on endpoints and elsewhere.

16. What Is An Actuator?

Typically, the actuator is used to disclose operational data about a running application, like health, statistics, metrics, dump, env, and so on. To allow us to connect with it, it will employ HTTP endpoints or JMX beans. Once this requirement is added to the classpath, we have access to a number of endpoints right away.

17. How to share data between microservices?

These are three of the most common microservices data sharing paradigms.

  • Messaging – Messages are exchanged between applications via a message broker. Messages are routed to interested parties via topics & queues via the broker. You don’t require service discovery or orchestration because data providers & clients communicate to a message broker & exchange data across topics.
  • Sharing Data Stores – A relational database, a NoSQL store, or any data storage service can be shared by services. The data is published to the database by one or maybe more services, and it is consumed by other services as needed.
  • RESTful Services – It’s simple to construct and manage RESTful services. “Stacking” APIs makes perfect sense when both internal services & external clients need accessibility to the same information. Duplication is avoided by reusing interfaces.

18. What is RESTful?

RESTful web services/Representational State Transfer (REST) is an architectural approach that allows computer systems to interact over the internet. Microservices are easy to comprehend and deploy because to these web services.

19. How to handle failover in microservices?

To handle failures, you can use one of the following strategies –

  • Across internal microservices, utilize asynchronous communication (for instance, message-based interaction).
  • Use exponential backoff retries. When  a service is unavailable for a short period of time, this strategy helps to avoid brief & inconsistent failures by executing call retries a specific number of times.
  • Avoid network timeouts by working around them. Clients should be developed in such a manner that they do not block forever and always employ timeouts when awaiting a response. Using timeouts guarantees that resources aren’t ever idle for an extended period of time.
  • Make use of the Circuit Breaker design. The client process in this technique keeps track of the number of unsuccessful requests.
  • Make sure you have backup plans. When a request fails, the client process performs fallback logic, such as providing cached data or a default value, in this manner.
  • Limit the amount of queries in the queue. Clients should also establish a limit on how many outstanding inquiries a client microservice may submit to a certain service.

20. What is Domain-Driven Design?

Domain-driven design (DDD) often promotes modelling that is based on business realities as it pertains to use cases. DDD will discuss challenges as domains in the context of developing applications. Furthermore, if we are developing complicated microservices with a substantial business rule, DDD methodologies are used.

21. Is microservices a web service?

Microservices are a type of architecture that is relatively new. It is built on the foundation of web services. It might, however, be any service that is designed as a stand-alone feature with its own database & can be deployed autonomously.

A web service is something that is expected to “handle” with HTTP – in other words, it performs something on the internet. A microservice, on the other hand, is not bound by the WWW environment. A microservice is designed to deliver one unique service at its core, however the http protocol, for example, is not restricted.

Similarities between both –

  • Both are service specific.
  • Cost-Effectiveness
  • Pluggability
  • Language and Platform Agnostic
  • Require small development teams

22. What is OAuth?

The acronym OAuth stands for open authorization protocol. This protocol enables you to use HTTP to access client apps from third-party sources such as GitHub and Facebook. It enables you to exchange resources from one site with another without requiring their credentials.

23. Where are APIs’ used in Microservices?

Consider the following scenario: you’ve constructed the e-commerce application mentioned above using Microservices. There are three services available, including customer, cart, and product service. Now, how do you suppose these services will communicate to complete the client’s request?

That’s done through the APIs. As a result, each of these microservices will have its own API for communicating with the others. E ven if one microservice fails, the application will not be affected. Instead, just that particular feature will be unavailable, and if it is restored, APIs may reprocess the request and return the necessary answer to the client.

24. Differences between Microservices and APIs’

Microservices are a web application architecture approach that divides functionality into mini web services. APIs, on the other hand, are the frameworks that developers use to connect with a website.

Microservices – An architectural style that allows you to create applications in the form of discrete, self-contained services.

APIs – A set of procedures and methods that let a user to utilise an application’s underlying service.

Apart from that, APIs are an element of microservices and so assist these services in connecting with one another. However, each service has its own CRUD processes to save important data in its database while talking with the other services.

25. How do microservices communicate?

These are the ways in which microservices communicate:

  • HTTP communication – For service-to-service communication, HTTP calls between services is a viable option. There are synchronous HTTP calls between services, with no coupling between them. Those services that sent requests, on the other hand, must wait for a response before taking any action. Another alternative for communication between two services is an HTTP asynchronous call. In the case of several requests, the service takes the first service’s request & responds with a URL right away. This URL is used to see how far the request has progressed. Because the coupling is loose, the services do not have to wait for their answer. The services are separated from one another.
  • Message communication – The participating services do not contact directly with each other in message communication. To communicate with other services, the services send messages through a message broker.
  • Event-driven communication – The services in an event-driven paradigm do not need to be aware of any common message structure. Individual services provide events that facilitate communication.

26. What is End to End Microservices Testing?

End-to-end testing ensures that each step of the workflow is working properly. It also guarantees that the system as a whole functions properly and meets all criteria.

27. What are java microservices?

Java microservices are a collection of software applications development in the Java programming language (which often make use of the huge ecosystem of Java frameworks and tools) that are created for a specific purpose and work together to produce a larger solution. As the name indicates, each microservice has extremely limited capabilities in order to provide a highly modularized overall design.

A microservices architecture is similar to a factory assembly line, with each microservice serving as a station along the line. Microservices are similar to stations in that each is accountable for a single job.

Each station & microservice is “skilled” in its area of responsibility, ensuring that the workflow & outputs are efficient, consistent, and of high quality. In a production setting, on the other hand, each station is in charge of constructing the complete product. This is similar to a single-process monolithic software programme.

28. What is Semantic monitoring in Microservices?

Semantic monitoring mixes automated testing with application monitoring. It helps you to figure out why your company isn’t making more money.

29. Do microservices need containers?

When describing a Microservices architecture, containers are frequently utilised. However, relying just on physical deployment completely misses the essence of Microservices. Deployment flexibility is an outcome of getting well-defined parameters for autonomous services.

The sheer volume of Microservices information focuses nearly exclusively on physical deployment & all of the technological challenges that come with it. Containers, Docker, Kubernetes, and Serverless become the focal points. However, this completely misses the concept of Microservices.

Microservices are about conceptual separation rather than physical isolation. A logical border defines a bounded context. It denotes a section of a bigger system’s subdomain.

30. Explain Conway’s Law?

“Any organisation that will develop a system has to generate a design whose structure will be a duplicate of the company’s communication structure,” according to Conway’s Law in microservices. This will have a huge influence on how software is produced, especially if microservices and Domain-Driven Design are used.

31. Why use Container in Microservices?

Containers are the most convenient and efficient way to handle microservice-based applications. It also aids in individual development and deployment. Docker also enables you to incorporate your microservice, as well as its dependencies, in a container image. These components may be used by microservices without any further work.

32. Why Docker is used?

Docker provides a container environment in which any programme may run. This software programme, as well as its supporting dependencies, are neatly bundled together.

33. What are the three commonly used tools for Microservices?

  • WireMock
  • Docker
  • Hystrix

34. What is Spring Cloud?

Spring Cloud is a system integration tool that connects to external systems. It enables the microservices architecture to create apps with limited data processing capabilities.

35. What are the uses of reports & dashboards in the Microservices environment?

Microservices may be monitored and maintained with the use of reports and dashboards. There are several Application Monitoring Tools available to help with this.

36. What are the difficulties that come with adopting Microservices?

  • 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 operational overhead.
  • To handle heterogeneously dispersed microservices, you’ll require trained people.

37. What cases microservice architecture best suited for?

Microservice architecture is ideal for desktop, web, smart phones, Smart TVs, and wearables, among other things.

38. What are some famous companies that use Microservice architecture?

The majority of large-scale websites, such as Netflix, Twitter, and Amazon, have progressed from monolithic to microservices design.

39. What are Client certificates?

A digital certificate used to perform authorised requests to a distant server is known as a client certificate. A client certificate is what it’s called.

40. What’s the use of PACT in Microservices architecture?

It is an open source application that allows service providers and users to test interactions. It is, however, distinct from the contract that was signed. This improves the Microservices applications’ dependability.

41. What is a CDC?

The Consumer-Driven Contract (CDC) is a contract that is driven by consumers. It’s a pattern for creating Microservices that may be used by other systems.

42. What are Reactive Extensions in Microservices?

Rx stands for Reactive Extensions. It’s a design pattern that lets you to acquire data by calling different services and then combining the results. Rx is a common distributed system technology that operates in the opposite direction of historical flows.

43. What does the term ‘Continuous Monitoring.’ mean?

Continuous monitoring is a technique for identifying and resolving compliance and risk concerns in a company’s operational & financial environment. It consists of people, procedures, and working systems that enable efficient and effective operations.

44. What Are Some Of The Most Common Mistakes Made When Migrating To Microservices?

  • Frequently, the developer will neglect to describe the existing difficulties.
  • The present programmes will be rewritten by the programmers.
  • There will be no clear definitions of responsibilities, timelines, or boundaries.
  • They fail to identify and implement a scope of automation from the start.

45. What is The Future of Microservice Architecture

The market for microservices architecture is expanding. According to Market Analysis, the market for microservices is growing at a CAGR of 17% and is anticipated to pass $33 billion by 2023. Cloud-based solutions, such as Software as a Service (SaaS) & Platform as a Service (PaaS), are accelerating the use of microservices, which break a big program into smaller, modular services that interact with one another via APIs.

The future of microservices will emerge in a variety of interesting and challenging ways.

By integrating microservices as well as an event-driven architecture, developers may build distributed, scalable, fault-tolerant, and extendable systems that receive and process enormous volumes of real-time event information.

Microservices enable development teams to add new features without having to make adjustments or rewrite substantial parts of current code on the fly. Monitoring microservices allows you to verify the design and performance of your service as well as detect potential troubleshooting issues. Companies understand the benefits of microservice design. Adoption of a hybrid cloud by various end-users and sectors is a key element impacting the growth of the microservices industry.

Serverless architectures have brought the central cloud plus microservice patterns full circle. A measured & organic approach will benefit the organization by easing the procedures required to manage an IT Cloud with microservices without relinquishing power and reverting to the monolithic past.

Tijendra January 12, 2022
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