Microservices vs Monolith Architecture

The way we build the architecture of applications has changed the evolution of technologies. Docker, Cloud services and Container Orchestration services has given us to develop more scalable, reliable and distributed solutions. In this article, we will compare monolith and micro-services architecture and will discuss what projects or products should use what type of architecture. We will explore their benefits and drawbacks.

Monolithic Architecture

Monolith is an ancient word referring to a huge single block of stone.In software engineering, a monolithic pattern refers to a single indivisible unit.Usually, a monolithic app consists of a database, client-side user interface, and server-side application. A monolithic architecture is comfortable for small teams to work with, which is why many startups choose this approach when building an app. 

Micro-service architecture

The idea is to split your application into a set of smaller, interconnected services instead of building a single monolithic application. Micro-service is a type of service-oriented software architecture that focuses on building a series of autonomous components that make up an app. Unlike monolithic apps built as a single indivisible unit, micro-service apps consist of multiple independent components that are glued together with APIs.

Let’s discuss the pros and cons of each, point by point.

Deployment

Monolith applications allow you to set your deployment once and then adjust it based on ongoing changes. There is only a single point of failure during deployment.If something goes wrong, you could break your entire project and you must redeploy the entire application on each update.

Microservices require much more work. You will need to deploy each and every micro-service independently. If something goes wrong, you don't need to break entire project. You will only break one small micro-service.

Maintenance

If you plan to use a monolith architecture, you do not need to get a DevOps for your team rather you can prepare yourself by familiar with orchestration tools like Docker, Kubernetes or any similar tools. Don't need to monitor and maintain the functioning state of your CI configuration.

On the other hand, if you have plan to use a microservices architecture, get a DevOps for your team and prepare yourself. Not every developer will be familiar with Docker or orchestration tools, such as Kubernetes or any similar tool that could help you to manage infrastructure with a lot of moving parts.Someone has to monitor and maintain the functioning state of your CI configuration for each micro-service and the whole infrastructure.

Reliability

Monolith is the looser here. Breaking anything affects whole application and causes issues for the clients whole application.

Microservices is the obvious winner here. Breaking one micro-service affects only one part and causes issues for the clients that use it, but no one else.For example, you’re building a banking application and the micro-service responsible for money withdrawal is down, this is definitely less serious than the whole app being forced to stop.

Scalability

Monolith applications are hard to scale. If you run more workers, every worker will be on the single, whole project, an inefficient way of using resources.

Microservices are again better suited here.With microservices, this is much easier. Resources can be used more carefully and allow you to scale only that parts that require more resources.

Cost

Cost is tricky to calculate because monolith architecture is cheaper in some scenarios, but not in others. For example, with the better scalability of microservices, you could set up an auto-scale and only pay for that when the volume of users really requires more resources. At the same time, to keep that infrastructure up and running you need a DevOps that needs to be paid. With a small monolith app, you could run on a $5-$20 host and turn on the snapshot. With a larger monolith app, you may host a very expensive instance because you can’t share it over multiple small, cheap hosts.

Development

Monolith all actions are performed with one directory, which provides for easier deployment. With a monolithic core, developers don’t need to deploy changes or updates separately, as they can do it at once and save lots of time.

Although microservices building procedure is a bit time consuming, the biggest advantage of microservices is that small single services can be built, tested, and deployed independently. The best way to deal with microservices is to build your docker-compose file from the beginning and develop through Docker. This helps you reduce the time spent onboarding new people; simply run the system from scratch and launch all microservices as needed.Doing code review and QA is simpler with microservices; you may even be able to write microservices in different languages.

Releasing

Monolith applications have a lot of internal dependencies that could not be broken up. There is also a higher risk that something you are committed to could depend on unfinished changes from your team members, which could potentially postpone releases.

Microservices that are smaller and with a proper architecture of micro-services communication allow you to release new features faster by reducing QA time, build time, and tests execution time.

What’s architecture better to you?

Monolith architecture if you:

1. Have a small team.
2. Don’t see performance bottlenecks for some key functionality.
3. Did not get millions in investments to hire DevOps or spend extra time on complex architecture.
4. Have experience of development on solid frameworks.

Microservices architecture if you:

1. Have a big team and knowledge of different languages.
2. Don’t have a tight deadline; microservices require you to research and architecture planning to ensure it works.
3. Worry a lot about the scalability and reliability of your product.
4. Have an existing monolith app and see problems with parts of your application that could be split across multiple microservices.

Summary

Building complex applications is inherently difficult. A Monolithic architecture better suits simple, lightweight applications.But anyway it is important to understand Monolithic architecture since it is the basis for microservices architecture where each service by itself is implemented according to monolithic architecture.The Microservices architecture pattern is the better choice for complex, evolving applications.

References:

Introduction to Microservices

Microservices Architecture Pattern

Monolithic Architecture Pattern

Distributed vs. Non-Distributed Computing

API Gateway Pattern