What are Microservices?

Microservices are an architectural approach to developing software applications as a collection of small, independent services that communicate with each other over a network. Instead of building a monolithic application where all the functionality is tightly integrated into a single codebase, microservices break down the application into smaller, loosely coupled services.

1. What are Microservices?

Microservice is a small, loosely coupled distributed service. Each microservice is designed to perform a specific business function and can be developed, deployed, and scaled independently. It allows you to take a large application and decompose or break it into easily manageable small components with narrowly defined responsibilities. It is considered the building block of modern applications. Microservices can be written in a variety of programming languages, and frameworks, and each service acts as a mini-application on its own.

2. How do Microservices work?

Microservices work by breaking down a complex application into smaller, independent pieces that communicate and work together, providing flexibility, scalability, and easier maintenance, much like constructing a city from modular, interconnected components.

Let’s understand how microservices work:

• Modular Structure:
  • Microservices architecture breaks down large, monolithic applications into smaller, independent services.
  • Each service is a self-contained module with a specific business capability or function.
  • This modular structure promotes flexibility, ease of development, and simplified maintenance.
• Independent Functions:
  • Each microservice is designed to handle a specific business function or feature.
  • For example, one service may manage user authentication, while another handles product catalog functions.
  • This independence allows for specialized development and maintenance of each service.
• Communication:
  • Microservices communicate with each other through well-defined Application Programming Interfaces (APIs).
  • APIs serve as the interfaces through which services exchange information and requests.
  • This standardized communication enables interoperability and flexibility in integrating services.
• Flexibility:
  • Microservices architecture supports the use of diverse technologies for each service.
  • This means that different programming languages, frameworks, and databases can be chosen based on the specific requirements of each microservice.
  • Teams have the flexibility to use the best tools for their respective functions.
• Independence and Updates:
  • Microservices operate independently, allowing for updates or modifications to one service without affecting the entire system.
  • This decoupling of services reduces the risk of system-wide disruptions during updates, making it easier to implement changes and improvements.
  • Also Microservices contribute to system resilience by ensuring that if one service encounters issues or failures, it does not bring down the entire system.
• Scalability:
  • Microservices offer scalability by allowing the addition of instances of specific services.
  • If a particular function requires more resources, additional instances of that microservice can be deployed to handle increased demand.
  • This scalability is crucial for adapting to varying workloads.
• Continuous Improvement:
  • The modular nature of microservices facilitates continuous improvement.
  • Development teams can independently work on and release updates for their respective services.
  • This agility enables the system to evolve rapidly and respond to changing requirements or user needs.

3. What are the main components of Microservices Architecture?

Microservices architecture comprises several components that work together to create a modular, scalable, and independently deployable system.

The main components of microservices include:

• Microservices: These are the individual, self-contained services that encapsulate specific business capabilities. Each microservice focuses on a distinct function or feature.
• API Gateway: The API Gateway is a central entry point for external clients to interact with the microservices. It manages requests, handles authentication, and routes requests to the appropriate microservices.
• Service Registry and Discovery: This component keeps track of the locations and network addresses of all microservices in the system. Service discovery ensures that services can locate and communicate with each other dynamically.
• Load Balancer: Load balancers distribute incoming network traffic across multiple instances of microservices. This ensures that the workload is evenly distributed, optimizing resource utilization and preventing any single service from becoming a bottleneck.
• Containerization: Containers, such as Docker, encapsulate microservices and their dependencies. Orchestration tools, like Kubernetes, manage the deployment, scaling, and operation of containers, ensuring efficient resource utilization.
• Event Bus/Message Broker: An event bus or message broker facilitates communication and coordination between microservices. It allows services to publish and subscribe to events, enabling asynchronous communication and decoupling.
• Centralized Logging and Monitoring: Centralized logging and monitoring tools help track the performance and health of microservices. They provide insights into system behavior, detect issues, and aid in troubleshooting.
• Database per Microservice: Each microservice typically has its own database, ensuring data autonomy. This allows services to independently manage and scale their data storage according to their specific requirements.
• Caching: Caching mechanisms can be implemented to improve performance by storing frequently accessed data closer to the microservices. This reduces the need to repeatedly fetch the same data from databases.
• Fault Tolerance and Resilience Components: Implementing components for fault tolerance, such as circuit breakers and retry mechanisms, ensures that the system can gracefully handle failures in microservices and recover without impacting overall functionality.

4. What are the Design Patterns of Microservices?

When a problem occurs while working on a system, there are some practices that are to be followed and in microservices, those practices are Design Patterns. Microservices design patterns are such practices which when followed lead to efficient architectural patterns resulting in overcoming challenges such as inefficient administration of these services and also maximizing performance. While working on an application, one must be aware of which design pattern to be used for creating an efficient application.

• Aggregator
  • It invoked services to receive the required information (related data) from different services, apply some logic and produce the result.
  • The data collected can be utilized by the respective services. The steps followed in the aggregator pattern involve the request received by the service, and then the request made to multiple other services combines each result and finally responds to the initial request. 
• API Gateway
  • API Gateway acts as a solution to the request made to microservices.
  • It serves as an entry point to all the microservices and creates fine-grained APIs for different clients.
  • Requests made are passed to the API Gateway and the load balancer helps in checking whether the request is handled and sent to the respective service. 
• Event Sourcing
  • This design pattern creates events regarding changes (data) in the application state.
  • Using these events, developers can keep track of records of changes made.
• Strangler
  • Strangler is also known as a Vine pattern since it functions the same way vine strangles a tree around it. For each URI (Uniform Resource Identifier) call, a call goes back and forth and is also broken down into different domains.
  • Here, two separate applications remain side by side in the same URI space, and here one domain will be taken into account at a time. Thus, the new refactored application replaces the original application.
• Decomposition
  • Decomposition design pattern is decomposing an application into smaller microservices, that have their own functionality.
  • Based on the business requirements, you can break an application into sub-components. For example, Amazon has separate services for products, orders, customers, payments, etc. 

5. What are the Anti-Patterns in Microservices?

Learning antipatterns in microservices is crucial for avoiding common mistakes. It provides insights into potential issues that can compromise system scalability, independence, and maintainability. By understanding these antipatterns, developers can make informed decisions, implement best practices, and contribute to the successful design and deployment of robust microservices architectures.

Below are the main 5 Antipatterns in microservices

• Data Monolith: Sharing a centralized database among microservices, undermining independence and scalability.
• Chatty Services: Microservices overly communicating for small tasks, leading to increased network overhead and latency.
• Overusing Microservices: Creating too many microservices for trivial functionalities, introducing unnecessary complexity.
• Inadequate Service Boundaries: Poorly defined boundaries of microservices, resulting in ambiguity and unclear responsibilities.
• Ignoring Security: Neglecting security concerns in microservices, risking vulnerabilities and data breaches.

6. Real-World Example of Microservices

Let’s understand the Miscroservices using the real-world example of Amazon E-Commerce Application:

Amazon’s online store is like a giant puzzle made of many small, specialized pieces called microservices. Each microservice does a specific job to make sure everything runs smoothly. Together, these microservices work behind the scenes to give you a great shopping experience.

Below are the microservices involved in Amazon E-commerce Application:

1. User Service: Manages user accounts, authentication, and preferences. It handles user registration, login, and profile management, ensuring a personalized experience for users.
2. Search Service: Powers the search functionality on the platform, enabling users to find products quickly. It indexes product information and provides relevant search results based on user queries.
3. Catalog Service: Manages the product catalog, including product details, categories, and relationships. It ensures that product information is accurate, up-to-date, and easily accessible to users.
4. Cart Service: Manages the user’s shopping cart, allowing them to add, remove, and modify items before checkout. It ensures a seamless shopping experience by keeping track of selected items.
5. Wishlist Service: Manages user wishlists, allowing them to save products for future purchase. It provides a convenient way for users to track and manage their desired items.
6. Order Taking Service: Accepts and processes orders placed by customers. It validates orders, checks for product availability, and initiates the order fulfillment process.
7. Order Processing Service: Manages the processing and fulfillment of orders. It coordinates with inventory, shipping, and payment services to ensure timely and accurate order delivery.
8. Payment Service: Handles payment processing for orders. It securely processes payment transactions, integrates with payment gateways, and manages payment-related data.
9. Logistics Service: Coordinates the logistics of order delivery. It calculates shipping costs, assigns carriers, tracks shipments, and manages delivery routes.
10. Warehouse Service: Manages inventory across warehouses. It tracks inventory levels, updates stock availability, and coordinates stock replenishment.
11. Notification Service: Sends notifications to users regarding their orders, promotions, and other relevant information. It keeps users informed about the status of their interactions with the platform.
12. Recommendation Service: Provides personalized product recommendations to users. It analyzes user behavior and preferences to suggest relevant products, improving the user experience and driving sales.

7. Microservices vs. Monolithic Architecture?

Below is a tabular comparison between microservices and monolithic architecture across various aspects:

Aspect	Microservices Architecture	Monolithic Architecture
Architecture Style	Decomposed into small, independent services.	Single, tightly integrated codebase.
Development Team Structure	Small, cross-functional teams for each microservice.	Larger, centralized development team.
Scalability	Independent scaling of individual services.	Scaling involves replicating the entire application.
Deployment	Independent deployment of services.	Whole application is deployed as a single unit.
Resource Utilization	Efficient use of resources as services can scale independently.	Resources allocated based on the overall application’s needs.
Development Speed	Faster development and deployment cycles.	Slower development and deployment due to the entire codebase.
Flexibility	Easier to adopt new technologies for specific services.	Limited flexibility due to a common technology stack.
Maintenance	Easier maintenance of smaller, focused codebases.	Maintenance can be complex for a large, monolithic codebase.
Testing	Independent testing of each microservice.	Comprehensive testing of the entire application.
Infrastructure Dependency	Less dependent on specific infrastructure choices.	Tied to specific infrastructure due to a shared codebase.

8. How to move from Monolithic to Microservices?

Below are the main the key steps to move from a monolithic to microservices architecture:

• Evaluate Monolith: Understand the existing monolithic application, identifying components for migration.
• Define Microservices: Break down the monolith into distinct business capabilities for microservices.
• Strangler Pattern: Gradually replace monolithic parts with microservices, adopting a gradual migration approach.
• API Definition: Clearly define APIs and contracts for seamless microservices communication.
• CI/CD Implementation: Set up Continuous Integration/Continuous Deployment (CI/CD) for automated testing and deployment.
• Decentralize Data: Transition to a database-per-service approach, reducing dependencies on a central database.
• Service Discovery: Introduce service discovery mechanisms for dynamic communication between microservices.
• Logging and Monitoring: Implement centralized logging and monitoring for visibility into microservices’ performance.
• Cross-Cutting Concerns: Manage cross-cutting concerns like security and authentication consistently across microservices.
• Iterative Improvement: Embrace an iterative approach, continuously refining and expanding microservices based on feedback and evolving needs.

9. Service-Oriented Architecture(SOA) vs. Microservices Architecture

Below is a tabular comparison between Service-Oriented Architecture (SOA) and Microservices across various aspects:

Aspect	Service-Oriented Architecture(SOA)	Microservices Architecture
Scope	Includes a broad set of architectural principles.	Focuses on building small, independent services.
Size of Services	Services tend to be larger and more comprehensive.	Services are small, focused, and single-purpose.
Data Management	Common data model and shared databases are common.	Each service has its own database or data store.
Communication	Typically relies on standardized protocols like SOAP.	Uses lightweight protocols such as REST or messaging.
Technology Diversity	Can have different technologies, but often standardized middleware.	Encourages diverse technologies for each service.
Deployment	Services are often deployed independently.	Promotes independent deployment of microservices.
Scalability	Horizontal scaling of entire services is common.	Enables independent scaling of individual services.
Development Speed	Slower development cycles due to larger services.	Faster development cycles with smaller services.
Flexibility	Can be flexible, but changes may affect multiple services.	Provides flexibility due to independent services.
Resource Utilization	Resources may be underutilized during low demand.	Efficient use of resources, as services can scale independently.
Dependency Management	Relies on shared components and centralized governance.	Each microservice manages its dependencies independently.
Adoption Difficulty	Generally requires more planning and organizational change.	Easier to adopt incrementally and suitable for agile development.

10. Cloud-native Microservices

Microservices and cloud each other by providing a flexible, efficient, and collaborative environment for building and running software applications

• Simplified Operations Cloud providers handle infrastructure maintenance and security, making it simpler for the microservices teams. They can focus on their specific tasks without worrying about the background technicalities.
• Cost-Efficiency Combining microservices with cloud resources is like paying for the exact tools and workspace you use. It’s cost-efficient because you’re not stuck with unnecessary equipment or space.
• Flexibility Need more teams or want to change your production process? The cloud allows you to adapt quickly, like rearranging workstations in a flexible workspace.

11. Role of Microservices in DevOps

DevOps and microservices are closely aligned and often go hand in hand to enhance the development, deployment, and operational aspects of modern software systems. Here’s a brief overview of how DevOps and microservices work together:

1. Continuous Integration/Continuous Deployment (CI/CD):
   • In a microservices architecture, each service can be independently developed, tested, and deployed. CI/CD pipelines are crucial for efficiently managing the constant updates and releases associated with microservices.
   • DevOps practices emphasize CI/CD pipelines, which involve automating the building, testing, and deployment of software.
2. Agile Development:
   • Microservices inherently support agile development by allowing teams to work independently on specific services, facilitating rapid iteration and deployment of new features.
   • DevOps promotes collaboration between development and operations teams, fostering agile development practices.
3. Continuous Monitoring and Logging
   • Microservices architecture requires robust monitoring to track the health and interactions between various services, aiding in early issue detection and resolution. DevOps emphasizes continuous monitoring and logging for real-time insights into application performance.

12. Benefits of using Microservices Architecture

1. Modularity and Decoupling:
   • Independent Development: Microservices are developed and deployed independently, allowing different teams to work on different services simultaneously.
   • Isolation of Failures: Failures in one microservice do not necessarily affect others, providing increased fault isolation.
2. Scalability:
   • Granular Scaling: Each microservice can be scaled independently based on its specific resource needs, allowing for efficient resource utilization.
   • Elasticity: Microservices architectures can easily adapt to varying workloads by dynamically scaling individual services.
3. Technology Diversity:
   • Freedom of Technology: Each microservice can be implemented using the most appropriate technology stack for its specific requirements, fostering technological diversity.
4. Autonomous Teams:
   • Team Empowerment: Microservices often enable small, cross-functional teams to work independently on specific services, promoting autonomy and faster decision-making.
   • Reduced Coordination Overhead: Teams can release and update their services without requiring extensive coordination with other teams.
5. Rapid Deployment and Continuous Delivery:
   • Faster Release Cycles: Microservices can be developed, tested, and deployed independently, facilitating faster release cycles.
   • Continuous Integration and Deployment (CI/CD): Automation tools support continuous integration and deployment practices, enhancing development speed and reliability.
6. Easy Maintenance:
   • Isolated Codebases: Smaller, focused codebases are easier to understand, maintain, and troubleshoot.
   • Rolling Updates: Individual microservices can be updated or rolled back without affecting the entire application.

13. Challenges of using Microservices Architecture

1. Complexity of Distributed Systems: Microservices introduce the complexity of distributed systems. Managing communication between services, handling network latency, and ensuring data consistency across services can be challenging.
2. Increased Development and Operational Overhead: The decomposition of an application into microservices requires additional effort in terms of development, testing, deployment, and monitoring. Teams need to manage a larger number of services, each with its own codebase, dependencies, and deployment process.
3. Inter-Service Communication Overhead: Microservices need to communicate with each other over the network. This can result in increased latency and additional complexity in managing communication protocols, error handling, and data transfer.
4. Data Consistency and Transaction Management: Maintaining data consistency across microservices can be challenging. Implementing distributed transactions and ensuring data integrity becomes complex, and traditional ACID transactions may not be easily achievable.
5. Deployment Challenges: Coordinating the deployment of multiple microservices, especially when there are dependencies between them, can be complex. Ensuring consistency and avoiding service downtime during updates require careful planning.
6. Monitoring and Debugging Complexity: Monitoring and debugging become more complex in a microservices environment. Identifying the root cause of issues may involve tracing requests across multiple services, and centralized logging becomes crucial for effective debugging.

14. Real-World Examples of Companies using Microservices Architecture

Organizations experienced a massive change while using microservice in their application, and that’s where the transition from monolithic to microservice came. You can go through some of the real-life examples in applications that use microservice are:

• Amazon: Initially, Amazon was a monolithic application but when microservice came into existence, Amazon was the first platform to break its application into small components, thereby adapting microservice. Due to its ability to change individual features and resources, the site’s functionality improved to a massive extent. 
• Netflix: Netflix is one such company that uses microservices with APIs. In 2007, when Netflix started its move towards movie-streaming service, it suffered huge service outages and challenges, then came the microservice architecture which was a blessing to the platform. 
• Uber: When Uber switched from monolithic nature to a microservice, it experienced a smooth way. Using microservice architecture, the webpage views and searches increased to a greater extent. 

15. Technologies that enables microservices architecture

• Docker:
  • Docker is a containerization platform that allows developers to package applications and their dependencies into lightweight, portable containers. These containers encapsulate everything needed to run the application, including code, runtime, libraries, and system tools, ensuring consistency across different environments.
• Kubernetes:
  • Kubernetes is an open-source container orchestration platform originally developed by Google. It automates the deployment, scaling, and management of containerized applications, providing features for container scheduling, service discovery, load balancing, and more.
• Service Mesh:
  • Service mesh technologies like Istio and Linkerd provide a dedicated infrastructure layer for handling service-to-service communication, traffic management, and observability in microservices architectures. They offer features like load balancing, service discovery, circuit breaking, and metrics collection.
• API Gateways:
  • API gateways such as Kong and Tyk serve as entry points for external clients to access microservices-based applications. They provide functionalities like routing, authentication, rate limiting, and request/response transformations.
• Event-Driven Architecture:
  • Event-driven architectures facilitate communication between microservices by allowing them to produce and consume events asynchronously. Technologies like Apache Kafka, RabbitMQ, and Amazon SNS/SQS provide scalable, reliable messaging systems for building event-driven microservices.
• Serverless Computing:
  • While not exclusive to microservices, serverless platforms like AWS Lambda, Azure Functions, and Google Cloud Functions can be used to deploy individual microservices without managing the underlying infrastructure, further decoupling and scaling services.

16. Conclusion

Now that you know “What are microservices“, it’s very important to have a practical idea about them by working hands-on on them. This article entirely answers all your doubts about microservices, their architecture, working, features, real-life applications, etc. Microservices are a must-known term in the case while building an application. Thus, it’s very important to have a good command of it.