Why Use MicroServices? Architectural Insights and Comparisons

Across various industries and sectors, the business environment today is incredibly complex and more competitive than ever before. At this time, it is quite easy and rapid for new startups to disrupt organizations by challenging their traditional business models along with the offering of new and innovative solutions. No matter the size of the business, proactive adoption of technological advancements and new trends is crucial to save your business and stay at the forefront. Otherwise, in the current dynamic business landscape, you’ll be hit the hardest, regardless of how big your customer market is, and how mature your processes are. As Nokia’s CEO ended his speech with a note, “We didn’t do anything wrong, but somehow, we lost.“‘We Didn’t Do Anything Wrong, but Somehow, We Lost….’” 2016. CUInsight. March 11, 2016. https://www.cuinsight.com/we-didnt-do-anything-wrong-but-somehow-we-lost/.”

When we talk about the ever-growing field of software development, scalable and resilient applications along with faster delivery time and reduced risks are the top-notch requirements of today's businesses. Development teams are breaking down their monolithic systems into a collection of smaller autonomous service components known as microservices. Here are some reasons why we use microservices:

• Monolithic architecturesA traditional software architecture where an entire application is built as a single, self-contained unit. are rapidly fading away from the software development landscape. The monolithic approach worked well where the application’s complexity remained minimal.

• Making a small modification in a monolithic application requires a complete rebuilding of the application, entire system testing, and deployment of the updated version of the application.

• To remain in the competition and rapidly respond to the never-ending demands of the business, organizations are moving toward loosely-coupled autonomous service units for developing their applications.

• Loosely-coupled architectures allow autonomous development and deployment of new features of the applications, and provide more engagement and productivity among teams.

What Are Microservices?#

Driven by the DevOps movementIt focuses on the continuous development and deployment of new features, and fixing bugs and security issues in software applications., microservices (also known as microservices architecture) has emerged as a popular approach that breaks down the software systems into a series of smaller, independently developed and deployed units to build a large and complex application. Each service unit focuses on performing a particular task and communicates with other service units using well-defined API (e.g. REST) but without knowing their internal working. This separation of concern, known as service boundaries, might be tied to organizational demands and hierarchy. For instance, user authentication services do not have any concern with payment processing services.

Service-Oriented Architecture vs. Microservices#

Service-oriented architecture (SOA) and microservices are both application architecture styles aimed to provide loosely-coupled, flexible, and scalable software applications. However, the distinction between SOA and microservices lies at the level of service types, which is a quite a bureaucratic classification.

SOA has four basic and domain-specific types of services including business, enterprise, application, and infrastructure services, whereas microservices has only two types of services: infrastructure and functional.

It's important to note that this categorization simplifies the types of services in microservices. However, in practice, microservices architectures can still include a variety of functional services that might align with different aspects of the business or application.

Additionally, there are a couple of important differences we must be aware of before selecting application architecture.

Why Use Microservices?#

Microservices offer several benefits to organizations, and shifting their software systems to microservices architecture can be a strategic move to grow and unlock new business potentials along with the provision of better user experience. The following are some of the compelling reasons to shift your applications to micro services.

Flexible Scaling and Faster Time-To-Market#

Software applications based on microservices architecture have the leverage to enhance the functionality and resources of any service component independently, based on the demand. As business grows, certain departments might need more resources as compared to others. The microservices model allows need-based extension and allocation of resources in an optimal and cost-efficient manner, since the microservices allow developers to work on their units without disrupting the other units. This would result in the shorter development and deployment time of new features and resources.

Fault Isolation and High Reliability#

In monolithic systems, a fault at any point of the system can choke the whole system. However, in microservices-based systems, we receive fault isolation, i.e., there is no single point of failure. An issue in a particular unit will not affect the services of the other units and the rest of the application will remain functioning independently. Similarly, we can update any service unit without disrupting and bringing down the entire system, making our software more resilient and reliable.

Flexibility in Development Tools and Technology#

Microservices promotes a culture of continuous learning and improvement; meaning that each team has the freedom to choose the most suitable tools and languages for their service units. This results in faster development time and keeps developers motivated by providing them with opportunities for continuous learning and improvement.

Characteristics of Good Microservices Design#

When considering how to build microservices, these are some of the key characteristics that define a well-designed architecture:

Scope of Responsibility#

Each microservice in a system should adopt the single-responsibility principle (SRP), which defines that each entity will be designed to perform a well-defined and single task or function. SRP is basically an OOP concept, which defines that every single object should be created to perform a single function. In other words, a class should have only one reason to change. This makes the SRP one of the most essential principles in microservice design because a microservice should not have multiple reasons to change. For example, the figure below shows a microservice architecture of an ecommerce application where each service has its own responsibility, making it easy to test and maintain.

Design for Failure#

We have seen many advantages of microservices over monolithic architectures. However, everything comes with its own challenges. Since microservices are smaller in size and specialized for a particular task, it makes development and maintenance easy. But things get complicated when we look at microservices at the system level and see how these services communicate with each other to perform a business operation. With an increasing number of services, the architecture complexity makes the system vulnerable to failures at various points. As a prevention measure, we have learned how to build microservices architecture for failures and design for resilience. We design and implement strategies for removing redundancies and graceful degradations without compromising the whole system.

Loose Coupling#

Loose coupling of microservices allows them to evolve independently without affecting the other microservices and promotes flexibility in scaling and development. To achieve this, unlike SOA, which often relies on an ESB for service-to-service communication, microservices should communicate with each other using APIs like REST, etc. The communication protocol should be simple and only responsible for transmitting and receiving data without transforming it.

Decentralized Data Management#

Unlike monolithic systems which have a central database for all the services, microservices architectures should define separate schemas and datastore for each service unit, using a bounded context pattern of domain driven design. A bounded context pattern ensures that the service is self-contained and specifies what can be entered and exited from the service. For instance, a customer places an order and the marketing department accesses and views this customer data. However, the billing department might see this customer information as a separate view.

Adoptability#

This is a concept similar to reusability in object oriented design. Adoptability determines the position of a service as a valued asset to the business, meaning how much this developed service is adoptable and reusable in multiple contexts. A service should be designed in such a way that it can deliver its services to multiple processes in the same or other business.

Autonomy#

Autonomy refers to the level of control a service implementation has over its runtime environment and database schema. When combined with statelessness, it plays a vital role in enhancing the overall performance, availability and scalability of the service. It ultimately provides a greater assurance to users about the quality of the service they can anticipate.

Scalability#

This is a key characteristic and advantage of the microservices architectures. It refers to the capability of an architecture to scale and deploy new instances of the service if it reaches its load capacity. We plan for the varying resource requirements of different services and employ horizontal scaling to handle increased demand and relieve pressure.

Thorough Documentation#

A good microservice architecture must be well-documented. Clear and up-to-date documentation of processes, services, dependencies, and API specifications must be available for developers, testers, and other stakeholders to understand the intricacies of the architecture. This will provide a clear understanding of the business processes and technical interfaces of microservices to all the interested parties. Consequently, the service should be published in a manner that guarantees that developers of client software have all the necessary resources to utilize it effortlessly.

Conclusion and Next Steps#

Microservices architecture is becoming a new norm and technological standard in the software development industry and has numerous advantages over conventional monolithic architectures. However, shifting our business to microservices model can be a strategic decision, resulting in unlocking numerous benefits including scalability, fault tolerance and resilience, enriched user experience, and faster time to respond to market demands.

Transitioning to microservices architecture should be taken as a long-term goal but the process should start promptly with gradual extraction of microservices from our existing monolithic system. This adoption of microservices architecture will set up a stage for the future growth of our business in this rapidly evolving digital landscape.