Why Modern Software Needs Microservices and Cloud‑Native Architecture

21CTO Guide: This article describes how to adopt microservices and suitable architectures, ensuring the correct build and overall architecture when using DevOps practices.

Why Architecture Matters

Without a good system architecture, organizations incur high costs. For example, an e‑commerce platform initially built with tightly coupled, non‑modular code mixes UI and business logic in the same source files, making future extensions to mobile or other clients costly and time‑consuming.

The main purpose of this article is to provide readers with a set of reference architectures that can serve as foundations for modern software projects.

Software architecture design considers three factors: distributed vs. non‑distributed, server‑side vs. client‑side, and monolithic vs. microservices.

Structure of the Article

Section 1 explains the concepts of monolithic systems, microservice architecture, and DevOps culture. Section 2 discusses software architecture and its importance. Section 3 introduces template architecture diagrams that can be used for modern applications, both monolithic and microservice‑based.

Below is an overview diagram:

Benefits of Proper Architecture

If designed correctly, modern software systems can support from dozens to tens of millions of users without changing source code. For instance, since 2009, Netflix leveraged AWS public cloud to increase traffic 100‑fold between 2013 and 2017, achieving unprecedented scalability.

Continuous integration and continuous delivery dramatically improve software quality and automated deployment. In 2011, AWS performed production upgrades every 11.6 seconds without affecting end users.

Monolithic approaches limit cloud scalability; despite their simplicity, they become bottlenecks for new technology trends.

What Is Software Architecture and Why Use It?

Software development aims to deliver functional requirements to end users and business stakeholders. Without following best practices and good architecture, developers may cram all functionality—including security, authentication, integration, and auditing—into a single large file, leading to maintenance challenges and poor long‑term operability.

Key quality attributes include functionality, reliability, efficiency, maintainability, and portability. Non‑functional requirements (quality attributes) are essential for reliability, maintainability, scalability, and security.

The SEI’s Attribute‑Driven Design (ADD 2.0) defines architectural importance through design purpose, quality attributes, primary functions, architectural concerns, and constraints.

Service‑Oriented Architecture (SOA) vs. Microservices

Over the past decade, many enterprises adopted SOA, which provides standardized interfaces for enterprise applications to achieve reusability and modularity. While SOA resembles microservices in reusability and flexibility, it often incurs high investment without proportional returns due to complex tooling, over‑design, communication overhead, and extensive automation requirements.

Key differences:

SOA uses heavyweight ESB pipelines; microservices use lightweight endpoints (e.g., HTTP).

SOA integrates large enterprise monoliths; microservices integrate small services within a project.

SOA is enterprise‑centric; microservices are project‑centric.

In SOA, business processes are managed by platforms; in microservices, they are coded at the application level and can be replaced by other services.

Modern Reference Architectures

The following classifications are based on deployment strategy (monolithic vs. microservice), distribution (distributed vs. non‑distributed), and coupling between server‑side and client‑side components.

1. Non‑Distributed Monolithic with Server‑Side Frontend

Applications are built using a three‑tier architecture running in a single process. Frontends may use JavaEE (JSP/JSF), Spring MVC (FreeMarker, Thymeleaf, JSP), while server‑side scripts like PHP or Python generate dynamic pages.

This architecture is simple to develop but suffers from limited scalability, maintainability, and security, and may struggle to support modern front‑end technologies.

2. Non‑Distributed Monolithic with Client‑Side Frontend

The frontend runs entirely on the client, while the backend operates as a server‑side process. Potential frontend technologies include traditional HTML/CSS/JavaScript, frameworks like Angular, Vue, React, native apps (Android, iOS), or hybrid solutions (Electron, Cordova, PhoneGap, Xamarin).

This separation allows independent evolution of the frontend without modifying backend code.

3. Distributed Monolithic with Frontend

The application is split into four layers, each running in a separate process and communicating over the network. This adds complexity but improves modularity, reusability, security, and scalability, especially when using asynchronous communication (event‑driven or JMS).

4. Non‑Cloud‑Native Microservices

Applications are modularized into independently deployable services, each managing its own database. This enables incremental development and horizontal scaling at the service level.

Challenges include early architectural decisions, service contracts, and communication protocols. While some advocate postponing monolith refactoring, the cost of re‑architecting can be high.

Potential technologies for microservices:

Spring Boot

Dropwizard

Java MicroProfile

Node.js

Python

Any technology that supports HTTP can be used to develop microservices.

5. Cloud‑Native Microservices

This architecture fully embraces cloud‑native principles and the 12‑factor app methodology, leveraging cloud platforms for elasticity and resilience.

For medium‑scale cloud applications this design may suffice, but larger systems may require additional infrastructure services such as those provided by Spring Cloud, Spring Boot Admin, or JHipster.

Conclusion

The article reviewed perspectives on software architecture for real‑world applications, covering definitions and importance of software architecture, microservices, DevOps, and SOA. As with any emerging trend, microservices and cloud‑native applications remain evolving, and debates around them will continue.

References: Martin Fowler and James Lewis, 2014, “Microservices”. Martin Fowler, 2015, “Monolith First”. Eberhard Wolff, 2016, “Microservices: Flexible Software Architecture”. Chris Richardson, 2018, “Microservice Patterns”. Josh Long and Kenny Bastani, 2017, “Cloud‑Native Java”. Matt McLarty, 2016, “Learning from SOA”. Ian Sommerville, 2016, “Software Engineering (10th Edition)”.