At the most basic level, monolithic architecture is a self-contained application while microservices will loosely couple a collection of services to create an application. While this article will examine both at depth, at a high level the move away from “all in one” solutions is a trend that shapes how businesses operate and how applications are developed.
The drive to stay competitive in an ever-changing technology landscape has led to explosive growth in microservices, which provide the agility and customizations organizations need to remain competitive.
In this guide, learn the difference between monolithic and microservices architecture, the pros and cons of monolithic vs microservices, how to choose the right fit for your project, and practical considerations for deployment.
76% of organizations are rearchitecting applications for microservices – Forrester Report
What is Monolithic Architecture
Monolithic architecture is the traditional approach to building a self-contained application that is often called a “single-tier” application. Its name is derived from that of a monolith: a single massive stone or rock. In a monolithic or traditional architecture, the application is made up of three main components that together create one code base:
- The user interface (UI)
- The business logic
- The data interface
The front-end / presentation layer / client-side
The application and server-side programming (part of the back-end)
The data access code that communicates the request to the database
These three parts are managed and served from one large code base that is then connected to the database (sometimes referred to as a fourth component).
What is an Example of Monolithic
The above simple diagram helps to explain monolithic architecture at the most basic level, but let’s dig down into how monolithic architecture would look for an eCommerce web application:
In this example, the client browser (represented as browser and device agnostic here) accesses the application, which displays UI to interact with the product catalog and completes the order with inprocess communication with one or more databases shared by the entire monolithic application.
Advantages of the Monolithic Architecture
A monolithic architecture is an “all in one” solution: a single code base deployed as a single unit. In general, this offers the following benefits:
- Low cost to develop for simple apps
- The architecture is easy to design, test and deploy
- Supports vertical scaling to share the workload and improve performance
- Eliminates cross-cutting concerns that exist when an application is spread across different modules (e.g. logging, performance monitoring)
Disadvantages of the Monolithic Architecture
There are times when an “all in one” solution is not ideal, leading to the main disadvantages of monolithic architecture:
- Updates to any part of the code base impact the entire code base, requiring full recompile of the app
- Any errors or server issues impact the entire application, impacting its overall reliability
- Code reuse is limited, often only supported with shared libraries (leading to coupling issues)
- Changes to any part of the app code become expensive due to dependencies in the code
- Code base can become large over time, marking it difficult to maintain and for new developers to jump in to contribute
- Does not support horizontal scaling (vertical scaling requires that the whole application be loaded onto multiple servers), so everything scales when only a part of the application may be experiencing a large load
- Tied to a single technology stack for everything
Monolithic apps are simple to develop, but over time tend to become large, difficult to manage, and complex to update.
What is Microservices Architecture
Microservices architecture decouples the front and back-ends of architecture, linking various independent services in the back-end (microservices) to the front-end via API. The microservices approach supports flexibility to choose and scale best of breed services as needed.
An increase in digital transformations, a proliferation of connected devices, and rise in adoption of cloud-based solutions augment the growth of the global microservices architecture market. – Allied Research
Principles of Microservices
The right principles can help developers build an application that performs and scales with ease. While some guides provide up to 10 principles of microservices, the best outcomes can be achieved by focusing on these three best practices:
- Single Responsibility
- Built Around Business Capabilities
- Design for Failure
The single responsibility principle (SRP) in programming states that every module should have responsibility over only one part of the app, narrowly defined and encapsulated.
Business logic is the core of microservices, with each service built around a business capability rather than a technical capability. Each business problem can be solved in a microservice that leverages its own tech stack.
To design for failure means to build resiliency into the core of the app. By defining boundaries around independent and encapsulated microservices, issues in one service should not affect other services. However, downtime is inevitable in every system, so designing for failure introduces how to degrade service if one or more components fails. For example, when Instagram is down (not fetching new content), it still supports browsing of cached content.
What is an Example of Microservices
To mirror the earlier example, let’s examine an eCommerce web app that takes advantage of a microservices architecture:
In this example, the user accesses the user interface, which then connects to each microservice independently when, and only when, they are needed. If the website suddenly sees a lot of traffic, the catalog service can be scaled up, with other microservices being scaled as much or as little as needed.
Microservices vs SOA Architecture
Service-oriented architecture (SOA) is another modular architecture, but one that leverages “services” – data as a service (DaaS), software as a service (SaaS) and platform as a service (PaaS). The biggest difference between microservices and the SOA model comes down to communication: in microservices, services are independent services whereas in SOA the services can communicate with each other to support the app, sometimes coordinating activities.
Interested in more of the differences between microservices and SOA? Drop a comment and we will develop a follow-up post or connect with you directly.
Advantages of the Microservices Architecture
Having read through the earlier section on monolithic application, it should come as no surprise that the benefits of microservices architecture solve many of the main problems with monolithic architecture, including:
- Components are only loosely coupled by API, with fewer interdependencies, making it easier to update or replace a module
- Microservices can be reused by other modules
- Module code base makes it easier for developers to learn each module, to find bugs, or to make changes
- Development is accelerated by the ability to reuse code, choose strong technologies and frameworks, and support iterative development
- Scaling is faster and cheaper since each microservice can scale independently and it’s easier to spot bottlenecks
- It’s designed for failure – one module going down will not impact the entire application
- Each microservice can use the technology stack best for its own operations
Disadvantages of the Microservices Architecture
While the advantages of microservices architecture seem obvious, like any other choice there are always drawbacks. The disadvantages of microservices architecture include:
- IT skills are needed for each microservice, so talent shortage can be an issue when so many frameworks and technologies are in use
- Microservices require more oversight on monitoring and logging each microservice
- Require more oversight to address security
- It can be difficult to decide where each module begins and ends – not all “components” are easy to define
- Moving code across services can be difficult if technologies differ
Monolithic vs Microservices
Now that this guide has introduced both monolithic and microservices architecture, the next sections will compare and contrast the two in terms of strategy, features, and how to make a choice between the two.
Monolithic vs Microservices Diagram
Microservices vs Monolithic Architecture: Deployment Strategy
While it is more obvious that monolithic architecture (one code base) is deployed in a traditional format to standard web servers, the same can not be said for microservices architecture. There are, in fact, a variety of approaches that can support microservices deployment including:
- One service-One host
Each service is deployed to just one virtual machine (host). This is the lowest cost and most straightforward option.
- One Service-One Container
Docker containers help to isolate microservices (one of the goals of good strategy) but to allow those containers to share resources such as operating servers, libraries, or frameworks.
- Serverless Deployment
Serverless deployments abstract and outsource infrastructure. While the program being created will run on a server, the servers are hosted and managed completely by a third party (cloud) who worries about all the patching, scaling, and load tasks.
Monolithic Architecture vs Microservices Architecture: Comparison
|Deployment||Simple and fast deployment of the entire system||Requires distinct resource, making orchestrating the deployment complicated|
|Scalability||It is hard to maintain and handle new changes; the whole system needs to be redeployed||Each element can be scaled independently without downtime|
|Agility||Not flexible and impossible to adopt new tech, languages, or frameworks||Integrate with new technlogies to solve business purposes|
|Resiliency||One bug or issue can affect the whole system||A failure is one microservice does not affect other services|
|Testing||End-to-end testing||Independent components need to be tested individually|
|Security||Communication within a single unit makes data processing secure||Interprocess communication requires API gateways raising security issues|
|Development||Impossible to disturb the team’s effort due to the huge indivisble database||A team of developers can work independently on each component|
Which Software Architecture to Choose
Having read through the comparisons and pros and cons above, the next step is to decide which software architecture is best for your organization and your project. Let’s examine why you should choose a monolithic architecture and compare that with why you should choose a microservices architecture.
Choosing a Monolithic Architecture
Choose monolithic architecture if the organization or project involves:
- Small Team
Monolithic architecture is ideally suited to the small business or startup. With a lean IT team, you can have deep experience in one technology stack to use for the entire application and not worry about skill shortages for different IT stacks, knowledge silos, or the ongoing management of a more complex microservice architecture.
- Simple Application
There is no need to reinvent the wheel for a simple application that is very straightforward and not likely to scale at an unprecedented pace.
- No Microservices Expertise
Effective microservices requires multiple people with expertise in specific services, technologies or frameworks as well as those who have experience in how to bring it all together to work well.
- Quick Launch
A simple application can be developed to prototype rapidly with a monolithic approach.
Choosing a Microservices Architecture
On the flip side, monolithic architecture is not ideally suited where organizations need to remain nimble against competition and where resources are at play to develop a large or complex app.
- A Complex and Scalable Application
Microservices will help the organization develop more complex software or app that involve a lot of business logic (operated by many different modules), either offering personalization or lots of features or heavy use of interactivity. Microservices is also ideally suited for those “breakthrough” startup apps or apps that reach a large audience and need to be able to scale rapidly.
- Microservices Expertise
If the team has access to, or can hire out, the right skills and knowledge, it’s possible to aim for a microservices approach to build and maintain an app built on microservices architecture. IT teams need experience in microservices, DevOps, containers and Cloud.
- Enough Engineering Skills
As above, microservices teams require enough in-house or outsourced skills in enough areas to develop each module / tech stack or to work with SaaS options for different modules.
- Excellent Cloud-based Infrastructure
Microservices relies on Cloud infrastructure to be effective and to scale appropriately (at the right speed, cost) as necessary. Make sure the cloud infrastructure chosen is flexible on pay and on technology to provide the greatest flexibility in architecture.
Monolithic vs Microservices Architecture: FAQs
- Should I start with a microservice or a monolith?
- Do microservices require a specific technology stack?
- Is monolithic architecture faster than microservices?
The choice to start with a microservice or a monolith (monolithic) comes down to the size and skill of the team, the needs of the program, and the desired time to market. While most conventional wisdom would suggest a small or start-up team leverage a monolithic approach, the clever use of outsourcing can help small teams future-proof their big ideas with a microservices approach.
No, each microservice can have its own tech stack, allowing developers to choose the right technology, frameworks, and libraries ideally suited for each module.
The question of speed always comes up in the monolithic vs microservices discussion, but there are two interpretations of speed: time to develop and performance. Simple monolithic applications are simple to develop, debug and deploy, but over time they can become difficult to scale and suffer from performance issues. On the other hand, the independent scaling capabilities of a microservices architecture make it ideal for high performance situations, but the number of API calls can be a drain on performance, making this a bit of a ‘push’ situation. From a development standpoint, ‘speed’ depends on the team. Microservices architecture is well suited to iterative, incremental development where sprints can focus on modules and accelerate time to market.
Which option is right for your organization, monolithic or microservices? Whether you want a steady and straightforward architecture or are looking for something innovative, Net Solutions has your back with the skills, experience, and bandwidth to help your idea scale.
Don’t be held back by lack of time, IT skill or experience. Net Solutions has experienced teams in many innovative technologies, frameworks, and libraries to help bring your idea to life – and to help support it in the short or long term as your organization grows.