Microservices Interview Questions

⌚ Why do you use the term "microservice"?

The SDLC technique known as microservices, often referred to as microservices architecture, is essentially the construction of big applications as a collection of discrete functional modules. It is one of the architectural ideas used in software development that is most frequently. This architecture not only facilitates simple maintenance but also speeds up development. Microservices are also a huge benefit for the most recent approaches to software development, like DevOps and Agile. Furthermore, it supports the rapid, regular, and reliable delivery of large, complicated applications. Applications are conceptualised as groupings of the following services:
• testable and maintainable
• In loose coupling
• autonomously deployable
• based on or arranged according to business skills
• tiny staff in charge

⌚ What are the main advantages of utilising microservices?

The creation of an application to gather small autonomous services created for a business area is the main advantage of employing microservices. Therefore, the development teams may quickly create new app components to suit the requirement if the business has to change frequently. To accomplish a business objective, each microservice runs a distinct operation and communicates using a clear, simple mechanism, like a container. Additionally, it enables an organization's technology stack to develop.

⌚ List the key characteristics of microservices.

Microservices have a number of key characteristics, including:
• Decoupling: Services are substantially separated within a system. The entire programme may consequently be built, modified, and scaled quickly.
• Componentization: Microservices are seen as separate parts that are simple to swap out or upgrade.
• Business capabilities: Microservices are comparatively straightforward and just concentrate on a single function.
• Team autonomy: Each developer completes their task independently of the others, hastening the project's completion.
• Consistent software releases are made possible through methodical automation of software creation, testing, and approval (continuous delivery).
• Microservices do not prioritise initiatives that are applications. Instead, they view applications as products that they are in charge of.
• Decentralized Governance: The objective is to select the best tool for the job. Developers can select the ideal tools to address their issues.
• Agile development is facilitated by microservices. New features can be readily created and then removed at any moment.

⌚ Which three Microservices tools are most frequently used?

The three most popular tools for microservices are as follows:

Wiremock
Docker
Hysrix

⌚ What's the operation of a microservice architecture?

An application's microservice architecture can be condensed into a number of modules that each separately carry out a single, well-defined standalone activity. See how the microservice architecture functions.
An application is broken up into a number of loosely linked modules, each of which serves a different purpose.
It is dispersed throughout data centres and clouds.
Each module of the programme is a stand-alone service or process that can be upgraded, replaced, or removed without affecting the other modules.
A microservice architecture allows an application to expand as its needs do.

⌚ What does the term "monolithic architecture" mean to you?

The software components of an application are all contained in a large container known as a monolithic architecture. Within the application, these applications are combined into a single bundle.

⌚ How does the architecture for microservices operate?

The elements of a microservice architecture are as follows:
• Clients: Requests are sent by numerous users using various devices.
• Identity providers: They verify the identities of users or customers and provide security tokens.
• Client requests are handled via API Gateway.
• All of the system's material is contained in static content.
• Management - Determines failures and balances services across nodes.
• A tool for determining the path of communication between microservices is called service discovery.
• Distributed network of proxy servers and associated data centres is called a content delivery network.
• Information stored on a network of IT devices can be accessed remotely with the help of a remote service.

⌚ Which benefits of employing microservices are the most notable?

Here is a list of some of the most significant benefits of employing microservices:
• Microservices offer a wide range of technologies. It blends well with various databases, libraries, and frameworks.
• Due to the fact that microservices group small autonomous services or processes, a process failure should not bring the entire system to a halt.
• It offers the minor and parallel teams excellent support.
• The deployment time is drastically shortened.
• autonomous deployment

⌚ Describe how monolithic, SOA, and microservices architecture differ?

• Monolithic architecture: This refers to the tightly packed software components of an application that is "like a large container." Typically, it is created as a single huge system with a single code base.
• A group of services that interact or communicate with one another is known as a SOA (Service-Oriented Architecture). Depending on the communication's purpose, it could just be a straightforward data exchange or it might include numerous services working together to coordinate an action.
• Microservice Architecture entails building an application as a group of compact, independent services organised around a particular business area. The functional modules are scalable, may be used separately, are designed to achieve particular business objectives, and interact with one another via industry-standard protocols.

⌚ What difficulties do you encounter when dealing with microservice architectures?

The issues frequently encountered while constructing a large number of smaller microservices are as follows.
• Component automation is challenging since there are so many smaller components. Therefore, we must follow the Build, Deploy, and Monitor stages for each component.
• Perceptibility: It becomes challenging to deploy, maintain, monitor, and pinpoint issues when a large number of components are kept together. It necessitates excellent perception of all the elements.
• Configuration management: Maintaining component settings across diverse environments can occasionally be challenging.
• Debugging: It's challenging to identify errors in every service. To track down issues, centralised logging and dashboards are crucial.

⌚ What is PACT in microservices?

PACT is an open-source software application that enables service providers and users to evaluate isolated interactions against agreements established to improve the reliability of microservice integration. It also provides support for a wide range of languages, including Swift/Objective-C, JavaScript, Ruby, Java, Scala,.NET, and Java.

⌚ Describe the methods used by independent microservices to exchange information?

Microservices can communicate with each other using:
Websockets for streaming and HTTP/REST with JSON or binary protocol for request-response.
an application that uses sophisticated routing algorithms as a broker or server.
Message brokers include RabbitMQ, Nats, Kafka, and others; each is designed to handle a specific message semantic. To completely automate your backend, you can alternatively use a backend as a service like Space Cloud.

⌚ Describe CDC?

By establishing an agreement between customers and service providers specifying the structure of the data communicated between them, CDC (Consumer-Driven Contract) essentially ensures service communication compatibility. A contract is what we call a pact like this. In essence, it is a design pattern used to create Microservices that are effectively utilised by external systems.

⌚ What do you mean by testing microservices from end to end?

End-to-end (E2E) microservice testing is typically an unorganised, expensive technique used to make sure that all components function together for an entire user journey. The user interface is typically used to simulate how it appears to the user. Additionally, it makes sure that every workflow process is operating correctly.

⌚ Describe the main types of testing used in microservices?

Microservice testing becomes fairly complex when working with microservices because there are several microservices that interact with one another. As a result, tests are grouped according to their difficulty:

• Tests at the botton level Technology-related tests, such as unit tests and performance tests, constitute the lowest level of testing. This entire process is automated.
• Tests at the medium level: These are exploratory tests, like stress tests and usability tests.
• Top-level tests: There aren't many acceptance tests in the top-level testing. The acceptance tests aid stakeholders in comprehending and confirming the characteristics of the programme.

⌚ What do you mean by container in Microservices?

Technologies for allocating and sharing resources include containers. The development and deployment of individual microservice-based applications is seen to be the most efficient and straightforward technique for handling such applications. You may also use Docker to package a microservice and all of its dependencies into a container image, which can then be used to instantly roll out new instances of the microservice.

⌚ What is impotence and when would one utilise it?

Idempotence is the quality of being able to perform an action again with the same outcome, i.e. as if it had been performed just once.
Application: Idempotence is employed at the remote service or data source to ensure that it only processes a single instruction when it receives multiple copies.

⌚ What does "distributed transaction" mean to you?

A distribution transaction is a particular kind of transaction in which two or more network hosts are involved. A transaction manager is in charge of creating and managing transactions in this transaction. If there are multiple peers involved in the transaction, subordinate or superior relationships are used for communication between the transaction managers of each peer. To provide transaction atomicity and isolation, the resource manager manages the resources and collaborates with the distributed transaction coordinator.

⌚ Explain the difference between Rest and Microservices?

Microservices can be implemented in a variety of ways. One of them is REST over HTTP. REST is also used to offer corporate data in other applications including web applications, API design, and MVC applications. On the other hand, in a microservices architecture, any individual system component can be designed, deployed, and scaled independently. A robust application can be built using some of the principles and best practises that microservices offer. So we can conclude that REST is a tool for creating microservices.

⌚ Why are reports and dashboards needed in microservices?

Microservices are generally tracked through reports and dashboards. For this, a variety of tools are employed.
The list of reports and dashboards used in microservices is as follows:
In order to determine which microservices expose which resources, reports and dashboards are employed.
Additionally, it is utilised to identify the services that are affected whenever a component is changed.
It offers a convenient location to go to if paperwork is needed.
It details the deployed versions of the components.
Additionally, it is employed to elicit maturity and conformity from the constituents.

⌚ What exactly do you mean by a tasklet in a microservice?

The Tasklet has a straightforward interface and an execution mechanism. It can be used to complete certain activities, such as executing queries or erasing files. The Tasklet interface in Spring Batch is used to carry out special activities, such as cleaning or setting up resources before or after any step execution.

⌚ What does Eureka mean in terms of microservices?

A programme called Eureka Server, also known as Netflix Service Discovery Server, keeps track of all client-service programmes. Eureka Server is aware of all client apps running on all different ports and IP addresses because every Microservice registers to it. It typically makes use of Spring Cloud and doesn't put a lot of emphasis on application development.

⌚ Describe how service discovery is implemented in a microservices architecture?

Although there are other configuration options for service discovery, Netflix's Eureka is the most effective. This is a simple process that doesn't significantly strengthen the application. Furthermore, a huge variety of web apps are supported. Spring Cloud offers a variety of annotations in order to simplify usage and obscure complicated ideas.

⌚ What do you mean when you refer to canary releasing?

Canary releasing is a method for introducing new software versions that involves testing the updated version or new code/features on a small group of users before making the complete infrastructure accessible to everyone. Canaries are released in coal mines to warn miners when hazardous fumes reach dangerous concentrations, which is how this approach got its name.

⌚ Non-deterministic tests: what are they? What steps are involved in getting rid of them?

NDTs, or non-deterministic tests, are unreliable tests that occasionally succeed and occasionally fail. These tests are repeated if they are unsuccessful. The following techniques can be used to remove nondeterminism from non-deterministic tests.

Quarantine
Asynchronous
Remote Services
Isolation
Time
Resource Leaks

⌚ What does the term OAuth mean?

Open authorisation protocol is known as OAuth. With the use of this protocol, you can access client applications for third-party service providers like Facebook, GitHub, and more. It enables you to share resources saved on one website with another without requiring their login information.

⌚ What do Microservices' Reactive Extensions do?

Another name for Reactive Extensions is Rx. It is a design pattern that enables assembling a combined answer by calling various services and gathering the responses. The widely used distributed system tool Rx operates in direct opposition to traditional flows.

⌚ What is Docker's primary function in microservices?

In general, Docker offers a container environment where any application can run. To achieve this, the application and the dependencies needed to support it are both securely packaged. Given that Docker is accustomed to doing this, these packed products are known as containers and are known as Docker containers. In short, Docker enables you to containerize your microservices and manage them more effectively.

How are microservices security tests carried out?

A microservices application is a grouping of more compact, autonomous, and functional modules that can be created in many programming languages, use various data sources, and perform on various operating systems. Because of this, testing the microservices as a whole is exceedingly difficult. The various components/modules must be individually tested. There are three typical methods for doing this.

Code scanning: To verify that each line of code is error-free and reproducible.
Flexibility: The security mechanisms should be adaptable to the system's demands.
Adaptability: Security protocols need to be flexible enough to accommodate harmful incursions.

What do you mean by Semantic Monitoring?

A portion of the application's automated tests are being executed against the operational production system during semantic monitoring or synthetic monitoring. These outcomes are tracked, and failure-related notifications are produced. From the standpoint of business transactions, Semantic Monitoring approaches microservice monitoring. Semantic monitoring determines how well the transaction runs for company and users rather than monitoring each component individually. At the same flow, it also recognises the problematic service layer and the accompanying microservice instance. This method shortens the repair wait time and enables quicker triaging.

How will Exception Handling be implemented in Microservices?

If an issue arises while handling an HTTP request, you must manually return the proper ResponseEntity in your controller or service and handle the exception. Here are some general guidelines for handling exceptions.
If you create exceptions, add @ResponseStatus.
Implement a @ExceptionHandler method on a @ControllerAdvice class to handle all other errors, or use a SimpleMappingExceptionResolver instance.
Add @ExceptionHandler methods to your controller to handle exceptions that are particular to the controller.
One thing to keep in mind is that methods on any @ControllerAdvice instance are never chosen before @ExceptionHandler methods on the controller. The order in which ControllerAdvices are handled is not specified.

What tools might be taken into account for administering a microservice architecture?

The primary tools for creating and managing a microservice architecture are:
• MongoDB is a distributed, open-source document-based database. Here, data is kept in JSON format with various document-specific structures. Numerous programming languages are also supported by it, including C, C++, C#, PERL, PHP, Python, Java, Ruby, Scala, etc.
• Full-text search engine Elasticsearch.
• It is an event queuing system, says KAFKA. The event queue is used to process every transaction, preventing the web-like random interactions between various services. • A microservice design becomes reliable and tidy thanks to Kafka.
• It is an automation tool that facilitates Continuous Integration and Continuous Development, according to JENKINS. It connects well with practically every tool and supports a wide variety of plugins.
• Application deployment and development environments are destined to differ in numerous ways, according to DOCKER. Issues with deployment result from this. Docker offers a static environment in which the programme may execute, preventing deployment problems.
• KUBERNETES: As an engine, Kubernetes manages the thousands of services that are active within an application.
• JAEGER: It is a free and open-source distributed end-to-end tracing tool. Jaeger tracks distributed transactions, aids in performance enhancement, and identifies service dependencies. In addition, it provides a root cause analysis.
• FLUENT: Logging in and keeping track of it is a big problem in a multiservice architecture, when all the different systems are governed by different programming languages, separate databases, and run in different operating systems. This problem is made simpler by Fluentd, which offers a single logging layer. Additionally, logs can be gathered and combined into a data source.
• PROMETHEUS is a monitoring tool that assists in ensuring that all services are operating as intended after the deployment of the application. A time-series data repository, that is. It gathers metrics from an application and presents them visually.
• Grafana: This software package offers analytics and monitoring in a variety of visual representations, including graphs, charts, tables, etc.
• It serves as a reverse proxy, NGINX. It serves as a single point of access for all API requests.

How can microservices be used to develop state machines?

Each microservice that has its own database is a deployable programme that can run independently. This makes it possible to build state machines through which we may define several states and events for a certain microservice.

🚀Conclusion

Finally, this page has come to an end. With the information on this page and a little research, you should be able to create your own programmes. In fact, little projects are recommended to help you develop your programming skills. You can't learn everything you need to know to be a skilled programmer in just one course. Whether you're a seasoned professional developer or a complete beginner, programming is a never-ending learning process.