Think of applications architecture as a roadmap, giving teams the best practices they need to follow to create an application that’s well-structured, reliable, efficient and user friendly. Applications architecture encompasses patterns and techniques that are proven to provide predictable, efficient results that are compliant with business requirements.
There are many architecture styles to choose from, with the following being the most common.
Layered architecture, also known as “N-tier architecture,” is a traditional style that is often employed in the creation of on-premises applications. It’s also associated with legacy applications and was once the go-to style for enterprise apps.
Using the layered architecture style, developers often work with several layers or “tiers,” which make up the application. Each layer has its own responsibilities, and the layers help developers manage functions and dependencies. These layers are laid out horizontally, meaning each layer can only call on the layers below it.
Also associated with legacy systems, a monolith architecture style involves a single application that contains all functionality within it. This makes for an application that is tightly coupled in how it’s developed, how it’s delivered, and how it interacts with services.
Updating and scaling a monolith application will have many implications on the application itself and the infrastructure beneath it. Making one change in its code means that the entire application will need to be released again, so updates generally only occur once a year.
Microservices architecture is more than just an architectural style, it’s also an approach to writing software. When using a microservices architecture, applications are broken into the smallest functional component, known as a microservice. Each microservice is independent of the others, able to function autonomously with no dependencies.
By being distributed and loosely coupled, microservices have no impact on each other. This means scaling and updating microservices-based applications is far easier. Plus, microservices-based applications have a higher fault tolerance, since one service failing won’t take down the rest.
You can consider both monolith and layered architecture to be traditional or legacy styles, and they differ greatly from the more recent microservices architecture. First and foremost, while the former are interdependent, microservices are distributed. While the former are tightly coupled, microservices are as loosely coupled as possible.
The goal of microservices architecture is to empower development teams with flexibility. Microservices developers can work much faster, reducing time-to-market on multiple accounts. For instance, developers can work on multiple microservices at once, and since they’re deployed independently of each other, there’s no need to rebuild or re-release the entire application just because a change is made to one service.
With all of this in mind, adopting microservices is about more than simply changing to a new applications architecture. Successful adoption of microservices requires a fundamental change in how developers see, plan, and approach projects. This is why microservices is more than just an architecture style: it’s also an approach to software design.
Countless companies have been quick to adopt microservices, but don’t fall victim to the “pixie dust” anti-pattern. Adopting microservices requires careful planning and consideration, and it starts with making sure that it aligns with your business’s bigger goals.
With layered architecture, the biggest benefit is that you can look at each layer as a separate concern, making problem-solving more straightforward. Likewise, you can test each layer individually and isolate them from one another, ensuring they don’t affect downstream layers. This also creates changeability, as you can replace one layer with another with relative ease.
Still, layered architecture has downsides and limitations, like the management cost of having too many layers and performance issues as you add layers. Leaky abstraction can also negatively affect the functionality of your layers, and layered architecture lacks the flexibility and scalability of microservices.
Like every architecture style, monolith applications have their strengths. For starters, logging, caching, performance monitoring, and other cross-cutting concerns are minimal since these functionalities affect only the one application you’re working with. Monolith applications are also easy to debug and test, simple to deploy, and straightforward to develop.
The weaknesses of monolithic applications center on complexity, which can contribute to difficulty managing and scaling them. Making changes can also be difficult, because of the tight coupling. Finally, it’s problematic when a team wants to apply new tech to a monolithic application, as it requires the entire app to be rewritten.
By far, the biggest strength of microservices architecture is that each component is independent, which means flexibility in deploying apps and updating them. Microservices also have excellent fault tolerance, and adding additional features is far easier compared to monolithic applications. Understanding and managing microservices-based apps is also easier since they’re divided into simple components.
With all of that in mind, microservices are not perfect. This distributed system requires complex modules and databases that need secure connections to work together seamlessly. There are also cross-cutting concerns, as you have to consider how to externalize monitoring, metrics, and logging without creating dependencies between services.
Still, microservices continue to gain popularity. Which style is right for your company? Contact us today to chat with an expert.
This is article 1 of 4 in a four part series on Application Architecture and Systems Integration. You can view the related articles at the links below — or simply click to download our comprehensive Operational Guide to App Architecture & Systems Integration White Paper:
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