The Advantages of Microservices vs Monolithic Architectures
The debate about monolithic and microservices architectures has gained steam recently, with companies like Amazon and Google switching to microservices. While one side of the discussion prefers the stability of monolithic applications, the other side prefers the flexibility that microservices offer.
And this prompts the question: should developers use a monolithic architecture or split their application into microservices?
In this article, we’ll explore the definition and working principles of monolithic and microservices applications. Continue reading to find out the pros and cons of using both software development models.
What is monolithic architecture?
When you build an application on a single-tiered layer of interdependent components, this architecture is called a monolithic architecture.
As the name suggests, a “monolithic” architecture consists of indivisible units coupled together to handle different operations in the application.
Core working principles of monolithic architecture
At its core, a monolithic architecture comprises the user interface, a server-side application, and a database (locally-hosted or cloud-based).
- The user interface contains HTML, CSS, and Javascript code that clients or users can see.
- The server-side application performs back-end operations like handling HTTP requests and retrieving information from the database.
- The database stores, receives, and processes all the incoming and outgoing data.
Monolithic architectures lack modularity, since you cannot decouple the components into independent parts.
Advantages of monolithic architecture
Simple to develop
Most developers and engineers prefer monolithic architecture because it is the traditional way of building software programs — you work with a single codebase for the entire application.
Easy to debug
Since you are working with a single codebase, the debugging process becomes more linear and straightforward. Testers can also run end-to-end testing services across the application’s entire architecture.
Undemanding to deploy
Monolithic applications are easy to utilize because you only need to deploy one file or directory. Also, the lack of modularity allows you to focus on a single, centralized ecosystem.
Suitable for small projects
When working on a small project, say a minimum viable product or proof of concept, you can use a monolithic architecture for the application. By doing so, you’ll save costs and deliver the MVP in time.
Adaptable to rigid projects
If you want to build an application that doesn’t require scaling, monolithic software architecture can solve your problems.
Fewer network issues
Although issues like network latency may occur, they are less frequent than with microservices.
Disadvantages of monolithic architecture
Gradual degradation
Monolithic architectures degrade gradually over time due to the constant addition of new components. Eventually, the application deteriorates to such a state that it takes longer to process requests.
Demanding to understand
As the codebase grows, the architecture becomes more complex to understand. For example, new developers hopping onto a new project will struggle to comprehend the changes to the entire codebase — even with air-tight documentation.
Difficult to scale
Monolithic applications present scalability issues because of their rigidity, which is a massive issue for companies seeking to grow and expand their services.
Challenging to maintain
Although most monolithic applications start as simple units, the architecture grows with time and becomes more complex. As a result, any repair effort will require a massive investment of time and resources.
Difficult to upgrade
Monolithic applications are challenging to upgrade. First, you need to find the module to update; then, you must implement inventive ways to integrate new services without breaking the entire application. And after making changes — no matter how minuscule — you must redeploy the whole application.
Susceptible to software vulnerabilities
Since monolithic software often has only one point of failure, any error or malware attack can crash the entire system. Even with rigorous testing, experienced QA specialists might struggle to find the source of this software failure.
What are microservices?
If your application comprises multiple independent units, this is the microservices architecture model. Microservices carry out specific functions controlled by unique databases for each component.
Core working principles of microservices architecture
When an application is split into microservices, the separate units carry out unique functions. Each unit contains servers and databases that are independent of each other — and can hence be reused in other processes.
Most importantly, the microservice architecture relies on business-oriented APIs that combine everything into a cohesive application. This gives them a higher level of modularity than monolithic architecture.
Advantages of microservices
Independent, reusable components
All the components of a microservice architecture are independent, allowing you to redeploy them in other applications without affecting other units.
Easy to debug
Since every microservice unit is a separate entity, developers and engineers can easily spot flaws in the application and fix them promptly. They can also conduct full-scale testing across multiple units — or pinpoint the problem area.
Easy to scale
With every microservice functioning on its own, you can choose the components to scale or leave as is. This attribute gives your application more flexibility and makes it scalable.
Simple to comprehend
Microservices are easy to manage if you have a basic understanding of the architecture. This clarity helps developers and testers spot issues faster and decipher ways to implement solutions.
Highly agile
Any application that uses microservices is agile. Making changes to one microservice allows you to redeploy it without disrupting other components. Also, you can add and test new technologies easily.
Disadvantages of microservices
Too complex
As the system expands, the microservices architecture takes on more components, making it more difficult to manage. You also have to deploy every service (microservice) independently.
Demanding for testing
When an application malfunctions, diagnosing the problem and debugging the code could be a massive challenge under certain conditions. For example, if the system is distributed across multiple, complex microservices, testers may not spot an easy fix, and often need to debug every unit separately to pinpoint the origin of the issue.
Expensive to maintain
Since every microservice requires individual servers and databases to run specific operations, the cost increases as you add more units. Additionally, you may need to hire engineers for specific microservices, which adds to the overall maintenance cost.
Vulnerable to security issues
The presence of multiple units in the distributed systems introduces various points of failure and vulnerabilities in the microservice architecture. Even if one microservice is affected, the others will continue functioning.
Differences between microservices and monolithic architecture in software development processes
These days, most tech companies model their software development processes on either the lean, waterfall or agile methodology. Some also have a unique DevOps approach dedicated to only software development.
But since 71% of companies use the agile model, let’s explore how it pertains to the monoliths and microservices.
Which type of architecture is better for your business?
According to O’Reilly, 61% of companies have implemented microservices over the past five years, with a 55% “complete success” rate. Also, data from DZone shows that 73% of companies believe that microservices will become indispensable for building next-gen software applications.
And with companies like Uber, Netflix, Amazon, and Spotify switching to microservices, it is no secret that the pendulum is swinging in the direction of microservices architecture.
Besides, microservices allow you to build applications with failure in mind. By factoring in possible downtimes and maintenance, you get better control over unprecedented shortcomings in the future.
But that doesn’t spell absolute doom for monoliths. Developers can still use a monolithic architecture to build lightweight applications that require no updates — a calculator application, for example.
Also, companies with small teams — working on a simple project or creating a proof of concept — can build monolithic applications. This architecture offers better performance, since shared-memory access is faster than inter-process communication.
And above all, engineers and developers are already exploring the idea of combining monoliths and microservices into the modular monolith — a hybrid module where the code powers a single application and enforces strict boundaries between different domains.
Shopify’s use of modular monoliths shows promise in the following areas:
- Improved scalability
- Decreased level of complexity (compared to microservices and traditional monoliths)
- Lower costs
- Strictly-bound dependencies
- Better code organization
Conclusion
Choosing between monoliths and microservices should follow a systematic approach to solving a specific software development problem, rather than simply following trends. Although tech giants are adopting microservices, your company or startup might not benefit from adopting this architecture.
Consult with your engineers and developers to determine the best course of action for your development processes. And most importantly, start working on a modular monolith architecture to get the best of both worlds.
