Chapter 2 -Introduction to Microservices (Part 2)
Published: 2023-09-27 23:48:16


## Chapter 2 -Introduction to Microservices (Part 2)

![chapter image](https://cdn-images-1.medium.com/max/2048/1*j6Tj9YkJp20Gpf_ui_df0A.jpeg)

In this chapter we continue learning about microservices, this time we going to retake all the learning from the previous chapter “[Chapter 1 — Introduction to Microservice](https://dev.to/josueparra2892/chapter-1-introduction-to-microservices-5a2c)” and we are going to complete our learning with two important topics, “When to use Microservices” and “Steps to define a microservice architecture”.

Let's start with this awesome travel that will help us to understand more about the wonderful world of microservices.

Note: if you are not reading the previous chapter I recommend you to take a look before starting, by [clicking here](https://dev.to/josueparra2892/chapter-1-introduction-to-microservices-5a2c) you can find the related article.

## Structure

In this chapter, we will discuss the following topics:

* When to use Microservices

* Steps to define a microservice architecture

## When to use Microservices

After studying and analyzing what a microservice is, its characteristics, and the differences with other architectural styles, it is time to delve deeper into microservices. This chapter will examine common scenarios where applying a microservices architecture is appropriate in our architectural design.

As mentioned earlier, the decision to use a microservices architecture should be based on the specific requirements of our application. Here are some key points that can help identify when to apply a microservices architecture.

### **“Dealing with a complex application architecture”**

Microservices architecture is a suitable choice under several circumstances, such as “**dealing with a complex application architecture comprising well-defined functionalities that can be effectively decoupled into independent modules”**.

![img](https://cdn-images-1.medium.com/max/3840/0*gM2kon-rLE5_JHfE.jpg)

The microservices approach enables us to leverage the benefits mentioned earlier in the previous chapter, as microservices architecture helps in service decoupling and provides a more modular, scalable, and maintainable solution.

For instance, consider an e-commerce application where clear domains like products and orders exist. In such cases, dividing the application into microservices, with one dedicated to product management and another for order management, proves beneficial. Each microservice adheres to communication rules while having well-defined contexts and functionalities. This results in a more cohesive and robust system architecture.

By embracing microservices architecture, the application gains flexibility and agility in development, empowers it to manage complexity more effectively, and with the right design, ensures a more resilient application, capable of handling varying demands and adapting to changing business requirements.

### “I**ndependent scaling**”

Microservices architecture proves particularly advantageous **“when certain parts of an application require independent scaling** **to manage varying workloads effectively”**.

![img1](https://cdn-images-1.medium.com/max/2688/1*lXoLRmVkytmg-9b1350fmg.png)

It is not always necessary to scale the entire application, this is where the implementation of microservices comes into play since on some occasions some components are used more than others. Considering the design of the application architecture, we can opt for microservices implementation. This strategic decision allows us to scale specific modules as needed, without the burden of scaling the entire application.

Returning to the e-commerce example, suppose the ordering service experiences higher demand compared to the service handling user data. In such a scenario, microservices provide the ideal solution, enabling us to scale only the microservice responsible for orders without the need to scale others that don’t require it.

By embracing microservices, we gain granular control over resource allocation, ensuring optimal performance, and efficient resource utilization. The ability to scale independently enhances the application’s resilience and responsiveness, making it an ideal approach for handling varying and dynamic workloads in today’s fast-paced and ever-changing digital landscape.

### “A**gility in development**”

Microservices architecture proves to be a preferred choice **“when agility in development and the rapid adoption of new functionalities are crucial requirements”**.

As highlighted earlier, the adoption of microservices significantly enhances the maintainability of our application. The independent nature of each microservice reduces complexity when implementing changes or introducing new features, ensuring that modifications in one microservice do not impact others.

With microservices’ flexible and adaptable architecture, integrating changes in response to evolving requirements becomes more streamlined and efficient. This adaptability allows development teams to respond quickly to business needs, accelerating time-to-market for new functionalities and features.

By embracing microservices, organizations gain a competitive edge, enabling them to stay nimble in an ever-changing market landscape. The modular and independent nature of microservices empowers development teams to be more responsive, innovative, and collaborative, ultimately driving business success in today’s fast-paced digital ecosystem.

### “R**educe the complexity**”

Microservices architecture is an ideal choice “**when** **aiming to reduce the complexity of an application”**.

![img2](https://cdn-images-1.medium.com/max/2000/0*DRFojnXBC3ahtIA0)

By its very nature, microservices offer a lightweight and modular structure for designing applications. This architectural approach not only eases the burden of maintenance but also simplifies testing and enhances software quality. Treating each microservice independently allows for focused development and evolution, ensuring that changes can be made more efficiently and tailored to specific needs.

The clear separation of functionalities in microservices results in a more manageable and maintainable system, making it easier to pinpoint and address issues when they arise. This, in turn, fosters a more agile and responsive development process, empowering teams to deliver high-quality software with fewer complexities.

By reducing the application’s intricacies, development teams can focus on delivering value and enhancing the user experience, while also ensuring the long-term sustainability and maintainability of the software.

### **“Multiple development teams”**

Microservices architecture is a highly beneficial choice **“when multiple development teams collaborate on different areas of an application and seek independence and autonomy in their responsibilities”**.

![img3](https://cdn-images-1.medium.com/max/2000/0*k618mDMsgD_prS5E.png)

For large-scale applications comprising multiple components, implementing a microservices-based solution proves to be an effective strategy. Assigning each microservice to a specific team allows for focused maintenance and development efforts.

This clear separation of responsibilities reduces inter-team dependencies, streamlining the process of implementing changes. Each team becomes responsible for deploying updates to their designated microservice, promoting a more agile and efficient development workflow.

### “N**eed to utilize different technologies**”

Microservices architecture is the ideal choice **“when there is a need to utilize different technologies and programming languages within an application”**.

![img4](https://cdn-images-1.medium.com/max/2000/1*wiKtcXH9smj2hVoKGkxmjg.png)

During the architectural design phase, we may identify specific functionalities that benefit from the capabilities offered by certain programming languages or databases. Microservices present an elegant solution to this challenge by enabling us to divide the application into distinct domains, allowing each microservice to be implemented using the most suitable technology for its specific requirements.

This approach not only promotes flexibility in development but also mitigates technological lock-ins. With microservices, teams can work with their preferred technologies, enabling them to innovate and optimize their respective microservices without being limited by the overall application’s technology stack.

embracing microservices architecture facilitates a harmonious integration of different technologies and programming languages. This freedom of technology selection enhances development efficiency and empowers teams to leverage the best tools for each microservice’s unique requirements, ultimately delivering a more resilient, maintainable, and future-proof application.

### **“Expected to experience exponential growth”**

Microservices architecture is indispensable **“when dealing with an application expected to experience exponential growth”**.

![img5](https://cdn-images-1.medium.com/max/2000/0*V_pi0P-KzkSNyDk3.png)

When an application is expected to have a high demand of usage, the implementation of microservices is vital since, as mentioned in their characteristics, they offer a high level of scalability and less complexity for their maintenance.

A microservices architecture allows different parts of the application to be developed and deployed independently, facilitating its evolution and growth.

the implementation of microservices architecture is essential to meet the challenges posed by the exponential growth of an application. Their scalable and maintainable nature not only ensures smooth operation during periods of high demand but also lays a robust foundation for future expansion and innovation.

### “F**ault tolerance**”

Microservices architecture is the optimal choice **“when greater fault tolerance is a priority”**.

![img6](https://cdn-images-1.medium.com/max/2000/0*pU5r9rGhnGjlkl4Z.png)

For applications that require high availability, microservices offer significant advantages in mitigating failures that may occur between different microservices. Their modular nature facilitates fault detection and resolution, ensuring that errors are isolated and swiftly addressed. Being more tolerant to faults, the microservices architecture helps the resilience of the system as it provides more stable performance.

By embracing microservices, the architecture inherently promotes fault tolerance, resulting in a more resilient system. The decentralized structure of microservices ensures that failures in one service do not cascade to impact the entire application. This isolation of faults allows other services to continue functioning without disruption.

Those use cases help to clarify the usability of the microservices and help to evaluate the applications and evaluate if the implementation of microservices architecture is the appropriate solution or if we should use a simpler architecture.

## **Steps to define a microservice architecture**

This topic will explore the essential factors that aid in defining the required microservices for an application. These points are closely related to the characteristics of microservices and align with the opportunities discussed earlier when considering the adoption of microservices.

It is crucial to emphasize that the points mentioned here are general and apply to a wide range of microservices solutions. However, it is essential to consider that each system may possess specific characteristics that necessitate careful analysis on a case-by-case basis.

The following is a list of the steps that could be followed when defining a microservice-based architecture:

![img7](https://cdn-images-1.medium.com/max/2000/1*-W8pDDBSfKcyphcjHGpeNQ.png)

### **Domain Analysis**

This is the first step and one of the most important, a good definition of the domain is crucial for the architecture decision. In this step, a good understanding of the different domains and responsibilities of the application is the base for identifying which functionalities can be treated as independent microservices.

### **Decoupling**

![img8](https://cdn-images-1.medium.com/max/2004/1*6RLdDQGy_JJxKv4kjyyK4w.png)

Once the domains are clearly defined, and all potential functionalities that can be transformed into microservices are identified, the next step is decoupling. Adhering to the principles of microservices architecture offers advantages in designing each microservice with a specific responsibility and ensuring its independence from other services. This decoupling enhances the system’s evolution and maintainability.

### **Granularity**

![img9](https://cdn-images-1.medium.com/max/3344/1*Ig_Djz1BfEJuFA8rienxOA.png)

This point may seem simple, but it is of utmost importance. When defining microservices, careful consideration should be given to their appropriate size. Avoiding microservices that are either too small or too large is vital to ensure an optimal architectural design.

### **Well-Defined Communication Interfaces**

![img10](https://cdn-images-1.medium.com/max/2004/1*TjZZf6S7Lme_hq7cP37L_A.png)

In designing microservices one of the challenges is communication. Is needed to ensure effective communication between microservices by making informed decisions on how they will interact with each other like synchronous or asynchronous communication. On the other hand, Clearly define well-defined interfaces for each microservice to facilitate seamless communication within the system.

### **Scalability and Fault Tolerance**

When designing microservices, it is vital to prioritize scalability and fault tolerance. Each microservice should be capable of independent scalability, enabling it to handle varying workloads effectively. Implementing fault tolerance techniques ensures system availability, enhancing the overall robustness of the system.

### **Independent Implementation and Deployment**

Strategies must be devised to facilitate the independent deployment and updating of each microservice. These approaches should adhere to the key principle that mentions “***changes in one microservice should not impact others***”.

### **Observability**

Establishing observability tools for each microservice to quickly detect and fix anomalies, as well as monitoring the performance and efficiency of each microservice and optimizing them when necessary.

### **Security**

![img11](https://cdn-images-1.medium.com/max/2628/1*ucJ-K4VBijhS36ygyMz0EQ.png)

When defining microservices, ensuring robust security measures is of paramount importance, especially for communication between each service. Implementing measures like “encryption,” “authentication,” and “authorization” is essential to safeguard communication and data transfer between microservices. Additionally, proper access control should be enforced to ensure appropriate utilization of the resources provided by the microservices.

### **Team and Culture**

![img12](https://cdn-images-1.medium.com/max/2560/0*HEwgAUpqCJXQl_wN.png)

To fully harness the benefits of the microservices architecture, it is advisable to form specialized and multidisciplinary teams for the development and maintenance of each microservice. This practice helps to cultivate a collaborative and agile culture to ensure the seamless implementation and success of microservices.

### **Integration Testing**

Conducting thorough integration tests on each microservice is an essential requirement to ensure seamless functionality and successful communication between them.

### **Documentation**

Creating comprehensive and up-to-date documentation for each microservice is crucial to ensure that other teams can easily comprehend and utilize them effectively. This documentation should be accessible, well-structured, and regularly maintained to support seamless collaboration and understanding among teams.

### **Version Management**

![img13](https://cdn-images-1.medium.com/max/2000/1*V2YGTfpAmMhL8d7n4B2ckQ.png)

It is essential to manage the versions of each microservice to ensure adequate and documented control of the updates and changes made. Keeping track of releases will allow efficient development management and make it easier to identify significant changes to the system.

### **Continuous Reassessment**

It is crucial to be willing to re-evaluate the microservices architecture based on evolving requirements and technologies. This ensures that the choice of microservices remains the best option for the project at hand. The adaptability and flexibility to adjust the architecture according to the changing needs of the project are essential to maintain an optimal and efficient system over time.

## Conclusion

Embracing microservices architecture is an intelligent choice for businesses seeking to build robust, scalable, and future-proof applications in the dynamic landscape of modern software development.

In conclusion, by carefully following these steps, considering the unique characteristics of microservices, and evaluating the use cases discussed in previous topics, we can craft a robust and efficient microservices architecture that caters to the evolving requirements of our application and ensures its sustained success in the long run.


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Next reading:
Chapter 3: https://dev.to/josueparra2892/chapter-3-domain-driven-design-and-microservices-371b