Explore topic-wise InterviewSolutions in .

Docker GENERALLY provides a container environment, in which any application can be hosted. This is accomplished by tightly packaging both the application and the dependencies REQUIRED to support it. These packaged products are referred to as CONTAINERS, and since Docker is used to doing that, they are called Docker containers. Docker, in essence, allows you to containerize your microservices and manage these microservices more easily.

Microservices architecture is a method of developing a large-scale application as a collection of small autonomous services developed for a business domain. Since its debut in 2011, microservices have become a popular technology, especially among organizations building forward-thinking applications. This list of Microservices interview questions was carefully constructed to assist the development community in their INTERVIEWS. HOPE these Microservices Architect Interview Questions would be helpful for your interview. 

Containers are useful technologies for allocating and SHARING resources. It is considered 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. 

Mike Cohn's Test Pyramid explains the DIFFERENT types of automated tests needed for software development. The test pyramid is basically used to maximize automation at all levels of TESTING, including unit testing, service level testing, UI testing, ETC. The pyramid also states that unit tests are faster and more isolated, while UI tests, which are at the top, are more time-consuming and are centered around INTEGRATION. 

In accordance with the pyramid, the number of tests should be highest at the first layer. At the service layer, fewer tests should be PERFORMED than at the unit test level, but greater than that at the end-to-end level.

As there are multiple microservices working together, MICROSERVICE testing becomes quite complex when working with microservices. Consequently, TESTS are CATEGORIZED ACCORDING to their level:

Botton-level tests: The bottom-level tests are those that deal with technology, such as unit tests and performance tests. This is a completely automated process.  
Middle-level tests: In the middle, we have exploratory tests such as STRESS tests and usability tests.   
Top-level tests: In the top-level testing, we have a limited number of acceptance tests. The acceptance tests help stakeholders understand and verify the software features.   

A reactive extension, also known as RX, is BASICALLY a design approach that calls multiple services and then generates a single RESPONSE by combining the results. The calls can either be BLOCKING or not blocking, synchronous or asynchronous. A popular tool in distributed SYSTEMS, Rx works exactly opposite to legacy flows.

MONITORING a system usually INVOLVES the use of reports and dashboards. Using reports and dashboards for microservices can help you:  

• Determine which microservices support which resources.   
• Determine which SERVICES are impacted whenever changes are made or occur to components. 
• Make documentation easy to access whenever needed.   
• REVIEW deployed COMPONENT versions.  
• Determine the level of maturity and compliance from the components.

There are many ways to set up service discovery, but Netflix's Eureka is the most efficient. This is a hassle-free procedure that doesn't add much weight to the application. It ALSO supports a wide range of web applications. A NUMBER of annotations are PROVIDED by Spring CLOUD to make its use as simple as possible and to hide COMPLEX concepts.

Eureka Server, also referred to as Netflix Service DISCOVERY Server, is an application that keeps track of all client-service applications. As every MICROSERVICE registers to Eureka Server, Eureka Server knows all the client applications running on the different ports and IP addresses. It GENERALLY USES Spring Cloud and is not heavy on the application development process. 

Usually, end-to-end (E2E) microservice TESTING is an uncoordinated, high-cost technique that is used to ensure that all components work together for a complete user journey. Usually, it is DONE through the user interface, mimicking how it appears to the user. It also ensures all processes in the workflow are WORKING properly. 

The TERM 'IDEMPOTENCE' refers to the repeated performance of a task despite the same outcome.  In other words, it is a situation in which a task is performed repeatedly with the END RESULT remaining the same. 
 
Usage: When the remote service or DATA source receives instructions more than once, Idempotence ensures that it will process each request once. 

DISTRIBUTED transactions are an outdated approach in today's microservice architecture that LEAVES the developer with severe scalability issues. Transactions are distributed to several services that are called to complete the transaction in sequence. With so MANY moving PARTS, it is very complex and prone to failure. 

Generally speaking, OAuth (OPEN Authorization Protocol) ENABLES users to authenticate themselves with third-party service providers. With this protocol, you can ACCESS CLIENT applications on HTTP for third-party providers such as GitHub, Facebook, etc. Using it, you can also share resources on one site with another site without requiring their credentials.

DDD (Domain-Driven-Design) is basically an architectural style that is based on Object-Oriented Analysis Design approaches and PRINCIPLES. In this approach, the business domain is modeled carefully in SOFTWARE, without REGARD to how the system actually works. By interconnecting RELATED components of the software system into a continuously evolving system, it facilitates the development of complex systems. There are three fundamental principles underlying it as shown below: 

• Concentrate on the core domain and domain logic. 
• Analyze domain models to find complex designs. 
• Engage in regular collaboration with the domain experts to improve the APPLICATION model and address emerging domain issues. 

CONTINUOUS monitoring involves identifying compliance and risk issues in a company's financial and OPERATIONAL environment. It consists of people, processes, and working systems that SUPPORT EFFICIENT and effective operations.

The semantic monitoring method, also called synthetic monitoring, uses automated tests and monitoring of the application to identify errors in business processes. This technology provides a deeper look into the transaction performance, SERVICE availability, and overall application performance to identify performance ISSUES of MICROSERVICES, catch bugs in transactions and PROVIDE an overall higher LEVEL of performance.