What Are Microservices?
Leslie Tsang
December 14, 2022
To be clear, there is no one-size-fits-all architecture; there is no best and worst architecture as well, only the most suitable one for your business.
Introduction of Microservices
Microservices architecture is a flexible and scalable software architecture that aims to make large software systems easier to develop, deploy and maintain.
The fundamental idea behind microservices is to split a large software system into multiple, relatively independent services and each service focuses on a single functionality.
Services in a microservice architecture are often processes that communicate over a network to fulfill a goal using technology-agnostic protocols such as HTTP or gRPC, which makes it possible for different services to be combined on demand to meet various business needs.
Evolution of Software Architecture
Let's start with using the monolithic architecture as a startup architecture. See what problems are encountered with different architectures as the business grows over time.
Monolithic Architecture
Monolithic architecture is designed to be self-contained, wherein the application's components or functions are tightly coupled rather than loosely coupled, like in modular applications. There are many benefits to using monolithic architecture, which is why many applications are still created using this development paradigm.
Overview of a typical monolithic application's deployment. This design undoubtedly makes deployment simpler, but rolling updates are challenging, which might be disastrous if a module fails.
For instance, monolithic apps could perform better in terms of throughput than modular ones. Since each component and the related component's code must be present for the application to be executed or compiled, monolithic apps may be simpler to test and debug.
Monolithic applications have been successful in the past. However, in the cloud era, more and more people are frustrated with Monolithic architecture as more Monolithic applications are being deployed to the cloud base environment. Change cycles are tied together - a change made to a small part of the application requires the entire monolith to be rebuilt and deployed.
Developers must recompile the entire codebase and reinstall the entire monolithic application after each update, not just the altered portion. This makes continuous or routine deployments challenging, which in turn reduces the agility of the application and team.
It can be challenging to maintain a monolithic application modular in good structure over time, which makes it challenging to maintain modifications that should only affect one internal module. Scaling calls for scaling the complete application instead of only the portions that need more resources.
Service-Oriented Architecture
Service-oriented architecture (SOA) is a software architecture that refers to an application composed of discrete and loosely coupled software agents that perform a required function, defining a way to use service interfaces to make software components reusable. These interfaces make use of widespread communication protocols, so they can be quickly added to new applications without requiring significant integration.
Overview of a typical SOA deployment. The impact of a single service failure is effectively reduced with such an architecture and the iteration rate of a single service increases.
Such an architecture is better equipped to manage team expansion, allowing each team to focus on the specific service itself. Release the team from the heavy load of the past, so they may concentrate on one task and do it correctly.
The following benefits of SOA vs monolithic architecture:
- Better maintainability: each service is a stand-alone entity, making rolling updates and maintaining them simple and risk-free for other services.
- Higher reliability: large blocks of code, such as those used in the monolithic architecture, are more difficult to debug and test than services. Consequently, SOA-based products become more dependable.
- Parallel development: a service-oriented architecture promotes parallelism in the development process since it has layers. It is possible to simultaneously create and complete independent services.
Microservice Architecture
Microservice architecture is a form of SOA that focus on building a series of autonomous components that make up an application. Unlike monolithic applications built as a single indivisible entire, microservice apps consist of multiple independent components that are glued together with APIs.
The scope of the architecture is the key distinction between SOA and microservices. In contrast to a microservice architecture, which is based on discrete services that may operate independently, an SOA model allows services or modules to be shared and reused throughout the whole organization. In other words, whereas microservices are focused on applications, SOA has an enterprise scope.
Additional differences, are summarized in the chart below:
| SOA | Microservices | |
|---|---|---|
| Architecture | Services are reused and shared at the enterprise level | Services are decoupled and operate independently |
| Granularity | Relatively large, modular services | Smaller, more flexible services that serve a specific purpose or function to the business |
| Communication | ESB | API |
| Coupling | Resource sharing/loose coupling | Bounded context |
| Interoperability | Supports multiple message protocols such as Simple Object Access Protocol (SOAP), Advanced Messaging Queuing Protocol (AMQP) and Microsoft Messaging Queuing (MMQ) | Uses lightweight, language-agnostic messaging protocols such as HTTP, Representational State Transfers (REST) or Java Messaging Service (JMS) |
| Data governance | Common data governance across the enterprise as a result of component sharing | No consistent data governance among teams due to the independent nature of services |
| Storage | Single data storage layer shared by all services within a given application | Independent data server or database for data storage for each service, as required |
Overview of a typical microservice's deployment
Scaling strategies for monolithic architecture and microservice architecture
To read more in detail https://martinfowler.com/articles/microservices.html
In comparison to monolithic architecture, microservices architecture is also more flexible to iterative development methodologies and Agile methods. Due to the loose interaction between the various components, they are also more scalable and capable to be tested separately. Additionally, modules have their own databases, communicate with one another, and speed up program starts.
Why Microservices Are Needed
Utilizing microservices may significantly boost the development delivery cycle's effectiveness and increase the process's agility. The combination of DevOps and microservices speed up the delivery of the change and new features. Microservices can be built faster than the typical large-scale software development project involving a monolithic application. It’s easier and faster to manage changes.
The change in microservices will be more fluid and smooth than monolithic ones. There are no waterfalls in the microservices development process, as you have with a monolithic application. Each microservice is independent and can be developed with any programming language or construct.
Failures in microservices are also less severe than failures in larger systems. A monolithic application's failure in one area typically has a significant negative impact on the entire system. In a microservices design, problems can be resolved more quickly and easily. You recognize it, keep it apart, and make up for it. If your architecture uses microservices, you can grow the microservices to get around a performance barrier. A monolithic application's operational waterfall can be avoided by promptly creating a new version of the flawed microservices.
The Benefits of Microservices
The benefits of microservices over traditional architectures include the following.
- Modularity: A large software system is split into several relatively independent services, each of which is responsible for accomplishing a specific function. This allows different services to be combined on demand to meet different business needs.
- Scalability: An important advantage of microservices architecture is scalability. Because each service is relatively independent, it is possible to dynamically scale up or down each service according to actual needs. This makes it possible to better cope with fluctuations in business traffic.
- Deployability: The microservices architecture allows each service to be deployed independently and in a flexible manner. This allows new features to be deployed more quickly and allows for rapid iteration without affecting the overall system.
- Easy to expand: Microservices architecture endows every service with single responsibilities and functions. Under such architecture, microservices are easier to update and reconfigure than modules in traditional software architecture, and the explosion radius of a single service failure is manageable.
- Easy to maintain: The microservices architecture makes each service smaller and responsible for performing only specific functions. This makes it easier to maintain and allows for faster fault repair.
- Technical heterogeneity: Microservices architecture makes each service no longer restricted to a specific technology stack. The data interaction between services can be realized through standardized interfaces, and the most suitable technology stack for the current service scenario can be used for service development to achieve the optimal solution.
Summary
Software architectures have evolved to cope with changing requirements, often integrating new concerns. Microservices architecture is gradually becoming popular in the cloud-native era. To build better microservices architecture, please visit APISIX, the best API gateway, and API7.ai for more commercial support.