Microservices vs. monolithic architecture: Understanding the difference

Microservices vs. monolithic architecture is a complex debate. Find out how they’re different, the pros and cons of each, and how Dynatrace can help you transition to microservices.

As the pace of business quickens, software development has adapted. Increasingly, teams release software features more quickly to accommodate customer needs. As a result, organizations are weighing microservices vs. monolithic architecture to improve software delivery speed and quality.

Traditional monolithic architectures are built around the concept of large applications that are self-contained, independent, and incorporate myriad capabilities. As developers move to microservice-centric designs, components are broken into independent services to be developed, deployed, and maintained separately. Shifting from monolith to microservices makes it easier to test, develop, and release innovative features more rapidly.

Data supports this shift from monolithic architecture to microservices approaches. IDC predicted, by 2022, 90% of all applications will feature microservices architectures that improve the ability to design, debug, update, and use third-party code.

According to IDC, the requirement of the digital economy to deliver high-quality applications at the speed of business has driven a shift to highly modular, distributed, and continuously updated microservices-based architectures that use cloud-native technologies. Combined with Agile or DevOps approaches and methodologies, enterprises can accelerate their ability to deliver digital services.

C-level executives “must race to reinvent their organizations for the fast-paced, multiplied innovation world,” says Frank Gens, senior vice president and chief analyst at IDC. “This means reinventing IT around a distributed cloud infrastructure, public cloud software stacks, agile and cloud-native app development and deployment, AI as the new user interface, and new, pervasive approaches to security and trust at scale.”

In developing critical applications and services, it’s crucial to understand legacy software development.

What is monolithic architecture?

Monolithic architecture is development where an application is built on a single codebase, and the code is unilateral. Generally speaking, monolithic architecture is composed of three parts:

• Database. This is usually a relational database management system.
• Client-side user interface (UI). The UI generally consists of HTML pages or JavaScript running within a browser.
• Server-side application. This handles HTTP requests and executive domain-specific logic. Additionally, it will populate HTML views directed to the browser and retrieve, update, and modify data from the associated database.

The number of modules within an application depends on an organization’s complexity and the corresponding technical features. However, in a monolithic architecture, the entire application — including dependencies — is built on a single platform with a single executable for deployment. So, to make changes to the system, the development team needs to build and deploy an updated version of the server-side app.

Monolithic architecture pros

• Easier to develop. Working with a single executable is simple. So, for straightforward applications or the beginning of a development project, a monolithic architecture is easier. However, as development progresses and complexities arise, monolithic environments can become a drawback.
• Easier to test. Due to the nature of the application, you can simply launch the app and test the user interface with a given tool. Using one executable means there’s only one application you need to set up for logging, monitoring, and testing.
• Easier to deploy. There’s much less complexity when working with a single executable. To deploy to other systems, you need to copy the packaged application to a different server and run it.
• Less complex and lower overhead. Microservices can become complex quickly. However, in a monolithic architecture, you can avoid additional costs associated with interservice communication, service discovery and registration, load balancing, distributed logging, distributed performance monitoring and management, and data management.

Monolithic architecture cons

• Too tightly coupled. Although a monolithic application can be easier to work with initially, it becomes more challenging as the application evolves. Development tasks, such as isolating services for independent scaling or code maintainability, become more difficult.
• App architecture is too inflexible to evolve. Today’s applications evolve quickly. As the application rapidly develops layers and interdependencies, it becomes increasingly challenging to understand the codebase and its underlying dependencies.
• Challenging during build, test, and release cycles. While simple applications are easy to work with, they are difficult to update. Developers may need to recode the entire application and service.
• Hard on DevOps. A significant part of DevOps discipline is effectively working in teams to distribute application and service development. Breaking monolithic applications into disparate parts that can be developed separately is challenging, which limits DevOps’ ability to work in a distributed fashion.
• Limited because of a single programming language. Most monolithic apps rely on a single programming language. The challenge is, as the application grows and becomes more complex, you may need to integrate components written in different languages. A monolithic app poses challenges in incorporating other parts of apps or services written in a different codebase. As a result, this hamstrings DevOps teams’ ability to add features and functions that could’ve been better written in a different programming language.
• Difficulty integrating third-party tools. It’s challenging to deploy a third-party tool that requires complicated connections to different parts of the monolithic application. Because the app can’t be broken into chunks, developers need to jump through hoops to integrate a single codebase with a third-party service with dependencies and other requirements. This complicates the adoption of third-party tools. Adding self-contained, third-party components to a single codebase with multiple dependencies requires complicated hookups to different layers of a monolithic application.

What is microservices architecture?

As opposed to monolithic architecture, microservices are an approach to developing a single app as a suite of small services. Each of those services runs in its own process and communicates with lightweight mechanisms. Microservices often accomplish this communication with an HTTP resource application programming interface (API).

Another critical factor is microservices’ capabilities are expressed with business-oriented APIs, and the implementation of the service is defined purely in business terms. Additionally, these microservices are independently deployable by fully automated deployment tools.

Finally, applying the principle of loose coupling minimizes the dependencies between services and users. This allows the development owners of certain services or parts of the application to change the implementation and modify the systems of record or service compositions without downstream effect.

Microservices pros

• Improved continuous integration/continuous delivery. Because the architecture decouples services, DevOps teams can scale complex applications in a more straightforward manner. Instead of one extensive application, teams can work on application pieces to ensure a better development pipeline.
• Better testing. With smaller services, it’s easier to test and monitor application performance and components. This simplifies visibility and enables faster testing of specific application parts.
• Easier deployment. Instead of deploying one large application, you can deploy specific services to support your application. Furthermore, you can deploy services independently without affecting downstream operations.
• Improved distributed team functionality. With independent services, teams can own parts of the development effort. Each team can develop, deploy, and scale services independently of other teams.
• Easier to understand. Microservice size is relative to the project and overall application. However, loose coupling and service separation make microservices and the entire application architecture easier to understand. A developer can focus on one service or see how different independent services affect the application overall.
• Faster performance. Microservices are decoupled and independent. Therefore, DevOps teams can better control application performance, so applications can start faster and run more efficiently. This improved performance makes developers more productive and speeds deployments.
• Improved fault isolation. With independent, isolated services, you can find application faults faster than with one monolithic executable. For example, you can isolate a memory leak to one service instead of an entire application. Additionally, you can adjust that service while allowing other microservices to support the application. A single memory leak could take down the entire application in a monolithic architecture.
• Less code and stack lock-in. You’re not limited to one codebase with microservices. This eliminates any long-term commitments to a technology stack. You can keep parts of the application on one platform while designing a new service on a different stack.

Microservices cons

• Additional complexity. Developers need to become accustomed to working with the complexity of a distributed system.
• Transition challenges. If an organization primarily uses monolithic applications, then it’s more difficult for teams to develop distributed applications. Teams need to do an inventory of exiting tools and development practices before moving to microservices. Remember, it’s often a massive undertaking to refactor an application built on monolithic architecture.
• Complicated testing. Because teams no longer work with one executable, they have more services and pieces of an application to test.
• Interservice communication needs. Unlike a single monolithic application, DevOps teams must ensure microservices can talk to one another. Developers need to deploy an interservice communication mechanism to support the app.
• Careful deployments. If an application spans multiple services, it will require careful coordination between teams to deploy it properly. Further, deploying and managing a system in production that’s composed of different microservice types introduces complexity.
• Increased resource consumption. Rather than a single application instance, DevOps teams must provision resources — memory, CPU, and disk — to accommodate each cluster or service requirement.

Microservices vs. monolithic architecture: What are the differences?

Monolithic vs. microservices architecture features two main differences at a high level:

• Monolithic architecture is a single, extensive, executable application.
• Microservices are a set of loosely decoupled services to support larger application deployments.

Microservices architecture provides a different approach to software development. In conjunction with cloud deployment technologies, API management, integration technologies, and microservices monitoring, microservices create an agile and efficient way to deploy large, complex enterprise applications. The big difference is your monolithic application is disassembled into a set of independent services, which are developed, deployed, and maintained separately.

Which software architecture suits your solution and business best?

Although many in the development space argue that microservices are better for developing applications, there are specific use cases for monolithic architecture:

• You’re just starting. Smaller teams that simply can’t tackle the broader requirements of a microservices architecture should stick to monolithic designs — or work with partners who can help the team transition to support microservices.
• You’re building a proof of concept or test software. If you need to test and deploy proofs of concept quickly, skip microservices and build a monolithic architecture to allow for rapid product iteration.
• You’re simply not ready for microservices. If your team has no microservices experience, start with a monolithic architecture. There is a lot of risk learning microservices as you build the application. So, either work with what you know or work with partners who can help you migrate to microservices.

Of course, there will be use cases to work with microservices from the start. Consider the following:

• Teams want service speed. Microservices allow for quick, independent service delivery.
• Teams want efficiency. With microservices, you’ll be able to deploy a highly efficient, easy-to-scale platform.
• An organization is growing. If you plan on growing your team and working with enterprise applications, go with microservices, as they enable you to scale up your team without introducing exponential complexity.

How to migrate from monoliths to microservices

As your company grows, your applications and services become more complex. Subsequently, to support a growing business, you need to ensure your apps and services can scale with it.

If you’re ready to migrate, new tools from Dynatrace can give you valuable information about whether you should break out certain pieces of the monolith. This approach allows you to do continuous experimentation, and it gives you fast feedback without changing a single line of code.

Monitoring microservices made easy

Leading organizations adopt microservices to make enterprise applications more agile and resilient. So, a significant part of ensuring a successful process is monitoring critical microservices.

Dynatrace’s PurePath makes it easier to monitor microservices. Its out-of-the-box distributed tracing and code-level insights provide end-to-end visibility across complex application environments.

By enlisting PurePath and the Dynatrace platform to automatically connect logs and traces, analyze them in real-time, and assemble the data for AI-powered analytics, organizations can more effectively and proactively optimize digital services to innovate faster and scale smoothly. PurePath also supports the latest cloud-native architectures. Therefore, teams receive intelligent observability for serverless applications, containers, microservices, service mesh, and integrating with the latest open-source standards such as OpenTelemetry. Check out the demo today.