Introduction
In this article, we have explained the top and most asked Microservices interview questions.
Microservices is a new application platform. It is mainly used for cloud development. These are deployed and managed independently of each other.
Let’s get started :
Microservices Interview Questions
- What is Microservices?
- What are the Main features of Microservices?
- What are the main components of Microservices?
- What are some of the main advantages of microservices ?
- What are some of the disadvantages of Microservices?
- What are the challenges in using Microservices ?
- What are some of the main differences between microservices and monolith (SOA) application structures?
- How does Microservices Architecture works?
- What is the spring cloud?
- What Problems Spring Cloud is trying to solve?
- List down some of the core engineering uses of Docker?
- What are the various types of tests for microservices application?
- Explain the role of an architect in Microservices architecture?
- What are Client certificates?
- What is PACT and Why it is used in Microservices architecture?
- What is OAuth?
- What is Two Factor Authentication?
- What are the types of credentials of Two Factor Authentication?
- Can we create State Machines out of Microservices?
- What are Reactive Extensions in Microservices?
What is Microservices?
Microservice architecture is called as microservices.
It is basically an architectural style which is used for the development of softwares for small and large systems.
This architecture helps in building the application. It develops application as group of multiple independent services. These services are built around one business domain.
It is like in real life, group of bee build their honeycomb. The group of Bee builds their combs by arranging the hexagonal wax cells. They first start with small parts and then build it into the large beehives.
The agenda behind the creation of beehives that each of the wax cells are related to each other but at the same time they are independent as well.
As all the wax cells are systematically arranged, they define a pattern which helps in holding the hive together and also preventing it from collapsing.
It is an ingenious structure as it makes sure even if one cell is damaged other will be unaffected. It makes easy to repair the damaged goods.
What are the Main features of Microservices?
Below are some of the main features of Microservices are :
- Service Distribution based on Business Capabilities.
- It allows multiple individually Deployable Components.
- It has Decentralized data management.
- Feature for DevOps Implementation.
- It has the feature to allow Hidden Component Complexity in order to avoid unnecessary microservices dependencies.
- Technical Independence feature.
What are the main components of Microservices?
Microservice Architecture has six main components , which are :
- Containers, Clustering, and Orchestration
- Cloud Infrastructure
- Enterprise Service Bus
- Infrastructure as Code Conception [IaC]
- Service Delivery
- API Gateway
What are some of the main advantages of microservices ?
It is indeed the most asked MicroServices interview questions.
Microservices has many advantages , which are mentioned below :
- It has very smaller code base so it is very maintainable.
- It provides better support for a small team to manage more.
- It supports the individual deployable units as well.
- Regular software releases is encouraged.
- Security.
- less code is required in microservices often times.
- Multiple services can be developed as well as deployed parallel.
- Overall development time is reduced.
- It is very flexible structure and applications are very easy to develop and takes less time.
- It is scalable and reliable.
What are some of the disadvantages of Microservices?
Microservices is great but definitely not perfect. It has some disadvantages which are mentioned below :
- It is sort of complicated as a whole.
- The complete end-to-end testing is difficult.
- It requires accurate pre-planning for success.
- It has very less control over the third party applications.
- It has modular dependencies which are hard to calculate and track.
- It has risk of malicious intrusion.
- It has some deployment challenges.
What are the challenges in using Microservices ?
Below are some of the problems which occurs while using Microservices. As mentioned below :
- Microservices requires you to be ready for operations overhead.
- Microservices is a heavily involved model.
- Heterogeneously distributed microservices are complicated so it requires advanced knowledge.
- It is difficult to track the issues.
- It requires the end to end testing.
What are some of the main differences between microservices and monolith (SOA) application structures?
SOA or a monolith is completely opposite of the microservices structure.
See the difference :
| SOA | Microservices |
|---|---|
| In SOA, all elements are dependent of each other. | Elements are independent of each other. |
| If one element fail, all other will also fail as they are dependent. | In one fail, does not mean all other will also fail as they are independent. |
| This structure is not much sturdy. | This is very reliable structure. |
How does Microservices Architecture works?
It is one of the most asked MicroServices interview questions.
Microservices architecture components and its tasks are mentioned , as follows :
Clients
Clients are basically users. These users send requests from different platforms and devices.
Identity Providers
The identity providers are engineers. They are used to authenticate the clientsβ identities. They then issues the security tokens for each identity.
API Gateway
This is simply a gateway where the client requests are handled.
Static Content
It is the place where all the assets are stored.
Management
The management is used for balancing the node services. It also identifies any potential failures.
Service Discovery
Service discovery is a tool. It acts as a guide. It helps in communication between microservices.
Content Delivery Networks
CDN or content delivery network is a distributed network of servers. It is used for delivering the data requested by a microservice.
Remote Service
This mostly enables the remote access to be able to get onto the network.
What is the spring cloud?
Spring cloud is basically the building blocks of a microservice and Cloud.
It provides many tools for developers which helps in building some of the common patterns in distributed systems.
Spring could offers tons of open source projects like Netflix. It uses the technique as Spring Boot starters.
Spring Cloud is used for below purpose :
- Configuration management
- Service discovery
- Circuit breakers
- Intelligent routing
- Leadership election
- Distributed sessions
- Cluster state etc.
It is one of the most asked MicroServices interview questions.
What Problems Spring Cloud is trying to solve?
Spring Cloud helps in solving below mentioned problems :
Reduces performance issues
It uses multiple overheads to it definitely reduces a lot of performance issues.
Complexity
It helps in reducing the complexity of Microservices like –
- latency issues
- bandwidth issues
- security issues
- overall capacity etc.
Load balancing
It improves the load balancing.
Service Discovery
It has service discovery which allows the application processes and services to operate within a cluster.
Hence , It’s easy for inter communication.
Solved redundancy issues
It solves the redundancy issues, which are pretty common in distributed systems.
List down some of the core engineering uses of Docker?
It has multiple benefits, which are mentioned below :
- Easier and simpler configurations.
- Productive and Practical development methods.
- Continuous monitoring of the service.
- Smooth deployment.
- Rapid prototyping.
- Ease of development.
- Consolidated server features.
- Easy to manage.
- Well designer application.
What are the various types of tests for microservices application?
Testing in Microservices is complex as there are multiple parts or services working.
Each the component is tested in different levels.
There are basically exists three levels, which are mentioned below :
Bottom level
Bottom level tests are fully automated.
All the Performance tests and Unit tests are performed at Bottom level.
Middle level
Tests as exploratory testing like Usability tests and Stress tests are performed at this level.
Top level
Top level is the highest level of acceptance tests.
They are very fewer in number when compared to other levels.
It tests the functional and working testing of the product.
Explain the role of an architect in Microservices architecture?
An architect in Microservices plays below mentioned roles :
- It decides the broad strokes regarding the layout of the complete software system.
- It makes sure that the components are mutually cohesive but not tightly coupled.
- It helps in deciding the complete components zoning.
- It learns the challenges faced daily as it works with coder.
- It might provide technical governance.
- It makes recommendations for certain tools and technologies.
What are Client certificates?
Client certificate is a type of digital certificate.
It is used by clients to make authenticated requests to a remote server.
Client certificates are very useful as it helps in :
- many mutual authentication designs
- providing strong assurances of a requesterβs identity.
What is PACT and Why it is used in Microservices architecture?
PACT is an open source tool.
It helps in performing testing interactions between the service providers and consumers.
It is used to improve the reliability of Microservices integration.
It has below mentioned uses in MicroServices :
- It is Used for implementing the Consumer Driven Contract in Microservices.
- It is used for testing the consumer-driven contracts between consumer and provider of a Microservice.
What is OAuth?
OAuth is used for accessing the resources of the resource owner.
It can be done by enabling the client applications on HTTP services.
Services like Github, Facebook etc.
So without the credentials, we can access the services from other services.
Spring Boot Example with OAuth2.
What is Two Factor Authentication?
Two-factor authentication basically used to enable the second level of authentication to an account log-in process.
See the diagram below :
What are the types of credentials of Two Factor Authentication?
There are basically three types of credentials. As mentioned below :
- Something you know. [PIN, PASSWORD, PATTERN]
- Something you have. [OTP, ATM CARD]
- Something you are. [FINGERPRINT, VOICE PRINT]
Can we create State Machines out of Microservices?
Yes, we can create state machines out of a Microservice.
As, Microservices own their own database as an independently deployable program unit. Hence, we can create state machines out of it.
For a particular microservice, we can specify different events and states.
For Example : we can define an Order Microservice.
An Order might have different states. In the Order microservice , the transitions of Order states can be independent.
What are Reactive Extensions in Microservices?
It is commonly known as Rx.
Reactive Extensions is basically a design approach. It calls the multiple services to collect all the result. It then compile a combined response.
The calls to the multiple services can be :
- synchronous or asynchronous
- blocking or non-blocking.Β
- Rx or Reactive Extension is a very popular tool. It is a distributed system.
Further Readings :
Conclusion
This article has explained top and most asked microservices interview questions with answers. If you are willing to attend technical interview in 2020 then this will help you.
Thanks for Reading!
