Monolithic VS Microservices Architecture: Should You Follow the Trend?

larity and are now considered a trend in designing software architecture.

Experienced developers though can argue on whether microservices are indeed a magic pill or not. While monolithic architecture is often called cumbersome and inconvenient, it’s been around for ages – and it’s still here, serving as a base for millions of software products. So what should you opt for when it comes to monolithic vs microservices? Let’s have a better look.

Monolithic architecture

A monolithic architecture of a software product is exactly what it sounds like – it’s designed as a monolith, tightly connecting main components together. Think of it as cementing the bricks in the wall: once you do it, it would be really hard to make a change to a single brick without somehow changing the others around it. Note though that it’s not bad at all: a monolithic application is relatively easy to develop and deploy (if it’s not too big) because there is only one unit to work on. 

A monolithic application has a single-tiered structure and encompasses all functions of an app. On the contrary, In a microservices architecture, these functions would be distributed across different microservices services. 

A monolithic application may contain a different number of components, but the essential ones would be a database (most often, relational) or several databases, a server-side application, and a user interface aka the client-side application. All components of a monolithic app perform as a single unit and any changes made to one will also lead to changes in the other two. Monolithic architecture is also considered a traditional approach to software development and it is highly suitable for certain projects. 

The pros of monolithic architecture

If you think that monolithic apps are a relic of the past, think again. Yes, they have certain issues (more on them below) but at the same time, monolithic applications have several benefits that are really hard to beat.

• Few cross-cutting concerns such as logging, caching, performance monitoring. Because the whole app acts as a single unit, it’s much easier to manage this area of the app’s functionality.
• Easier testing due to the monolithic nature of the app. With monolithic applications, you can perform testing much faster since you are testing a whole unit at once (unlike microservices).
• Easier and faster development and deployment due to the simplicity of the architecture. Since you have only one executable file or directory, you don’t have to worry about deploying multiple units and can work in a hassle-free manner.
• Easier database management since there is only one database. In this way, it becomes easier to handle the database and all related processes.
• Relatively quick start of a new project due to the simplicity of the architecture. It’s quite easy to start a monolithic application – the main issues may arise once it gets bigger and more complex.

The cons of monolithic architecture

Now it’s time to talk about the reasons why many developers tend to switch from monolithic to microservices architecture. While all these cons are not really critical, for certain projects they might become a real pain point so it’s important to understand them.

• Limited scalability due to the monolithic nature of the app. Because the whole app is a single unit, you can’t really scale certain components without scaling others (even if you don’t need to). Different components of the app also have different requirements towards resources so in the end, scaling a monolithic app becomes a huge headache.
• The limited and complex implementation of changes. Similar to the point above, the implementation of changes into the monolithic app can become quite a challenge due to the inability to work with single components separately.
• Development speed starts going down as the app becomes more complex. When your app starts to grow, it will require more and more time and resources for implementing the needed changes. 
• One issue can fail an entire app. Unfortunately, that’s true – if there is a single issue with a component, the whole app will most probably fail simply because all components are interconnected. This results in low reliability.

Who should use monolithic architecture?

As we already stated, monolithic apps have their right to exist and in some cases, they can even outperform microservices. Here are some of the most common use cases for monolithic architecture:

• When you have a relatively small and lightweight app and don’t plan to scale it much in the future;
• MVP development;
• When you have a small team and limited expertise (especially perfect for startups).

As you can see, all these use cases are united by several features: in all of them, the client does not have an overly complex and big app and an extensive team to manage it. The simplicity of monolithic applications is great for teams with a limited number of members and for small projects that need to be easily handled.

Microservices architecture

A microservices architecture means there are several independently functioning units and each unit can be seen as a separate service. In this way, every unit is responsible for a certain part of the application so if you need to work on a single part, others will function in the same way without any issues.

This type of architecture is sometimes called the rebranding of the existing SOA architecture (service-oriented architecture). This is not correct though. While microservices can be called an SOA-based approach to architecture design, SOA encompasses many more approaches (like CORBA) and is not limited by microservices only.

The communication in the microservices architecture usually happens via API, standard protocols, or by publishing messages to a broker and every unit has its own function. In this way, every component is also separately deployed and maintained and can be quickly updated upon request.

The pros of microservices architecture

So what are the benefits that make developers around the world go crazy about microservices? All of them are actually related to the nature of this architecture so it won’t come as a surprise but still, let’s have a look at them.

• Independent development and deployment of every unit. Since the components in microservices architecture are independent, that means you can easily work on the needed one while letting others function as they are.
• Fast time-to-market (though it will depend on the app’s business logic and other factors). Every component of a microservices app requires a specifically experienced team to work on it. Hence, such an approach speeds up the product release process.
• Various tech stacks and easy updating. An app with a microservices architecture may encompass several different technologies that are picked depending on what suits the project best. In this way, you choose the best option for each module and make the most out of it.
• High reliability due to the isolation of units. Unlike in monolithic architecture, in microservices in case one unit fails, the whole app will still be working.
• Separate scaling of app’s units. Each component can be scaled according to your needs while others can remain the same.

The cons of microservices architecture

While being awesome, scalable, and convenient, in some cases microservices architecture brings more harm than good. Let’s see what kind of challenges one may face when working with it.

• The complexity of the whole system due to the number of single units. In microservices, there can be hundreds of units in the microservice architecture and every unit has to be developed, deployed, and managed independently. So while the system is scalable, it’s also complex to handle. Note you have to manage the communication between the units too!
• Harder testing due to the number of independent units. With microservices, you get more code to check and you will probably need different testing approaches for different units.
• Possible performance issues due to the communication bottlenecks. When there are several units that communicate with each other, there is always a possibility of communication failures or issues. As a result, the performance of the app may slow down or even stop.
• Cross-cutting concerns. Unlike monolithic applications, microservices apps bring more cross-cutting concerns such as the need for externalized configuration, metrics, logging.

Who should use microservices architecture?

Even though there is a misconception that microservices suit everyone, that’s not very true. There are certain use cases for this architecture type that allow microservices to shine at their most and bring the best value to a project.

• When you have an evolving and complex application that will be scaled in the future;
• When you have 10+ interconnected modules;
• When you have a big team, microservices help in work standardization;
• When your app handles high traffic on a regular basis.

Bonus: microservices best practices

If you think that microservices are the most suitable option for your project, we collected several best practices that can help you manage and deploy the microservices architecture in an easy manner. All these tips are aimed at creating a scalable and high-performing app with a focus on security and reliability.

Keep microservices small

One of the biggest mistakes that one can make when working with microservices is loading them with multiple responsibilities. In reality, every microservice should have only one responsibility in order to minimize the possible negative consequences of a service failure. In simple words, if something goes down in a microservice, the failure will be sort of isolated. But if a microservice has multiple responsibilities, it might drag the whole system down in case of a failure.

Separate data storages

In some projects, all microservices are connected to a single database. This is considered an architectural mistake and can lead to conflicts such as coordination issues or data-model conflicts. Thus, it is recommended that every microservice has its own data persistence layer. In this way, microservices will be better isolated and damage will be minimized if the data set becomes unavailable for some reason.

Use the right orchestration tool 

If your company has hundreds of microservices to manage, you need an orchestration tool to handle them. Such tools are responsible for deployment and load balancing, as well as for provisioning, scaling, and communication management. Kubernetes by Microsoft is considered the leader in the field and is highly recommended by all its users. But if you want to look for an alternative, there are other options available too.

Summary

These days, it’s easy to forget that monolithic architecture exists on the contrary with microservices popularity. However, as we explained above, monolithic architecture remains strong and can provide you with robust and secure performance. The same goes for microservices: they can be extremely efficient and reliable if applied in the right environment.

Hence, when answering the question on what option to choose, always assess your project and consult the development team to see what would require less time and effort: monolith or microservices.