Monolithic vs Microservices: A Guide to Choosing The Right Architecture

Monolithic vs Microservices — what’s the best architecture for a business? This is a common question especially if you design and develop software. Both seem to have their pros and cons and it can become hard to choose.  

But with large companies like Netflix attributing their success to microservices, you know they can be valuable assets to your business. 

The question is — are they right for you? Let’s compare monolithic and microservice architectures and understand the differences that make them unique. 

By the end, you should have a fair idea of which architecture is best for you. 

Monolithic vs Microservices — At a Glance

It’s not just the implementation, but the thought processes that are different when we compare monolithic to microservice architectures. Let’s look at some of the major aspects that monolithic architecture differs from microservices. 

Aspect	Monolithic Architecture	Microservices Architecture
Definition	Traditional unified model. Self-contained and independent.	Collection of smaller, independently deployable services.
Advantages	Simple to develop and deploy. Enhanced performance. Less network latency.	Agility in development. Flexible scaling. Different technology per microservice.
Disadvantages	Difficult to manage as it grows. Lack of scalability and flexibility.	More complex. Requires skilled developers. Complicated independent deployment.
Deployment	One executable file or directory makes deployment easier.	Independent deployment of individual features.
Development Speed	Faster due to the simplicity of having an application based on one code base.	Can be slower due to complexity and more services in more places created by multiple teams.
Scalability	Cannot scale individual components.	If a microservice reaches its load capacity, new instances can be rapidly deployed to the accompanying cluster.
Reliability	An error in any module could affect the entire application’s availability.	High reliability. Changes can be deployed for a specific service without threatening the entire application.
Technology Flexibility	Constrained by the technologies already used in the monolith.	Allows teams the freedom to select the tools they desire.
Debugging	Easier with all code located in one place.	More complicated with each microservice having its own set of logs. A single process can run across multiple machines.
Cost Considerations	Generally lower cost.	Can lead to exponential infrastructure costs for each new microservice.
Security and Latency	Less network latency and security issues.	Potential for more network latency and less security.
Organizational Overhead	Generally lower as everything is centralized.	Added level of communication and collaboration needed to coordinate updates and interfaces.

What is the Monolithic Architecture?

Monolithic Architecture is a software development approach where the entire application is built as a single unified unit. All the business logic, database access, user interface, etc. are combined into one codebase and share the same memory space. 

This makes the application self-contained and independent, but also harder to change, as even small modifications may require rebuilding and deploying the entire monolith. 

As the codebase grows, monolithic architectures can become complex and slow to develop due to tight coupling between components.

Advantages

• Simple to Develop and Deploy: Developers can get started and keep adding code modules as needed, and the entire application code base and dependencies can be installed in a single environment, making deployment more straightforward
• Enhanced Performance: The unified structure of monolithic architecture allows for efficient data exchange mechanisms within the system, potentially leading to enhanced performance.
• Less Network Latency and Security Issues: There are fewer network calls between different parts of the application. This reduces network latency and can lead to fewer security issues.
• Focus on One Application: Monolithic architecture allows developers to concentrate on a single application, with all code located in one place. This can make debugging and tracing data movement within the same programming environment easier.

Disadvantages

• Difficult to Manage as it Grows: As the application grows, it can become complex and challenging to update or change over time. 
• Entire Redeployment for Small Changes: When developers introduce new changes to a monolithic application, they must retest and redeploy the entire system on the server.
• Lack of Scalability and Flexibility: The entire application must be scaled as requirements change, leading to resource wastage because not all parts of the application need to be at peak capacity.
• Difficult to Adopt New Technology: Monolithic architecture limits the ability to introduce new features and technologies in existing applications. There are multiple dependencies that slow down progress.
• Less Reliability: A minor error in the code base can cause the whole application to fail, presenting a single point of failure. 

What is the Microservices Architecture?

Microservices architecture is a way of building software applications as collections of small, independent services rather than as a single monolithic application. Each microservice focuses on completing one specific task or function. 

The services communicate with each other using well-defined APIs. This makes it easy to update, modify, or scale each service independently from the rest of the application.

Principles of Microservices

• Single Responsibility: Each microservice focuses on one specific task or function. This ensures the service stays focused and is easier to understand, modify, and maintain.
• Built Around Business Capabilities: Microservices align with organizational goals by building around business functions and capabilities. This allows for efficient responses to business needs.
• Design to be Failsafe: Microservices are designed expecting failure can occur. Isolating failure to individual services allows the overall system to stay functional when components fail

Advantages

• Agility in Development: Microservices allow for faster development and deployment cycles, as individual services can be developed, tested, and deployed independently.
• Flexible Scaling: Individual services can be scaled independently based on demand, allowing for more efficient use of resources.
• Supports Horizontal Scaling: Microservices support distributed systems where each component receives its own computing resources, allowing for independent scaling.
• Different Technology per Microservice: The independence of microservices allows developers to use different technologies and frameworks for different services, fostering innovation and flexibility.
• System Remains Intact if One Microservice Fails: The failure of a single microservice does not bring down the entire system, enhancing overall reliability.

Disadvantages

• More Complex: Microservices require more planning, design, and coordination, making the architecture more complex to implement and manage.
• Complicated Independent Deployment: Each microservice must be deployed independently, which can be more challenging and time-consuming.
• Network latency: The communication between microservices can lead to increased network usage and latency, potentially affecting performance.
• Less Secure and Difficult Debugging: Security can be more challenging to manage across multiple independent services, and debugging may require coordinated efforts across different parts of the system.

Learn more: The pros and cons of microservices

7 Steps for Transitioning from Monolithic to Microservices Architecture

Monolithic architecture is a great way to get your business started. It’s easy to implement and helps you ship quicker. But as you scale, onboard more customers, and have more features to work with, the same architecture can become difficult to maintain. 

The same was the case with Uber which decided to revamp its architecture using the Service-Oriented Architecture (SOA) principles — an older variant of the microservice approach.

Let’s look at the steps that they took to go from monolithic to microservices and how you can too.

Step 1: Determine If You Need to Change

If you are in the early stages of your company, a monolithic architecture can work well. But as you grow, you may start to feel limited by it. Some signs you may need to switch architectures:

• New features are hard to add and upgrade
• The codebase has become complex and hard to maintain
• It takes a long time to onboard new developers
• Deployments have slowed down significantly

For instance, Uber started with a monolithic codebase but eventually switched to microservices as their existing codebase became a bottleneck for scalability and continuous integration. The constraints of a monolithic codebase tend to become more apparent as a company and codebase grow. 

Step 2: Decide to Move to Microservices

The decision to switch from monolithic to microservices for your software can be a difficult one. There are a lot of people involved and months of worth of work with seemingly no returns. Considering the number of resources you need to redirect to this new project, it may also be hard to get executive buy-ins. 

Uber’s monolithic codebase had grown to over 500 features that they split into 500+ services. 

But switching to microservices helped Uber go from operating solely in New York to a fast-growing global ride-hailing service so quickly.

These microservices can operate independently leading to faster and more efficient development cycles giving Uber the upper hand when it comes to adding new features.

Step 3: Plan the Migration

Once you’ve decided to make the move and received executive buy-in, it’s time to plan things out. You need to identify the parts that can be broken down into microservices and select the right tools and technologies. The AWS Well-Architected Framework can help here.

Uber faced challenges in areas like obviousness, safety, and resilience. 

They needed a standard way of communication that provided type safety, validation, and fault tolerance. After evaluation of existing tools, they found Apache Thrift met their needs best. 

Step 4: Adopt Tools and Standards

Uber used Thrift, as it guarantees strict contracts that describe how to interact with each service. They also created lifecycle tooling to publish these clients to packaging systems. 

As you get started, you may benefit from using a tool like Dashbird. It helps you monitor all your services and infrastructure under a single dashboard and gather relevant insights. This can help make things much easier to manage as more of your software features are split into independent services.

Step 5: Ensure Safety and Resilience

Safety and resilience are paramount. Uber drew inspiration from fault tolerance and latency libraries like Netflix’s Hystrix and Twitter’s Finagle. They wrote libraries to ensure clients could deal with failure scenarios successfully.

When converting features into independent services, each service needs to be built with safety and robustness in mind. We want the clients to always have access to the required features and services. And it can be difficult with a lot of microservices running. 

Dashbird can help you track all the services so you can act to fix the broken ones quickly. And implementing safety checks provide redundancy to keep the connected clients up and running without interruptions in case of failures.

Step 6: Understand Tradeoffs and Setting Goals

Migrating to microservices has tradeoffs. The benefits of scalability and faster development must be weighed against increased complexity.

Uber considered the complexity, development time, resource allocation, and the possibility of new failure points while migrating to microservices. But, their goals were clear — improve scalability, allow for faster development cycles, and enter new markets with agility.

And microservices proved to be a valuable asset to achieve these goals. 

In your case, the tradeoffs might involve increased complexity in monitoring and managing multiple services, potential consistency issues, and the required investment in new tools and technologies. If you believe the switch will help you achieve the goals faster, it makes sense to allocate the resources for the big revamp. 

Step 7: Implement the Transition

The last step is actually making the transition happen. This is when you put everything you planned into action. Uber did it slowly, moving one feature at a time into microservices. They kept testing to make sure nothing broke during the process.

You can follow a similar process:

• Break features into separate microservices, so each one does one specific thing.
• Choose tools and frameworks that fit your needs. Tools for monitoring and managing the microservices, like Dashbird, will be here.
• Test thoroughly before switching over. Check microservices individually and together while monitoring the performance of all the connected clients.
• Monitor closely and be prepared to fix any issues promptly.
• Roll out gradually rather than all at once, in case you need to roll back.
• Prepare documentation for all the changes and new services to help other devs understand the architecture
• Continuously monitor, analyze, and adapt your microservices as needs change. After all, that’s the beauty of moving to microservices. 

With planning, smart tools, and gradual implementation, moving to microservices can make systems more flexible, robust, and scalable. It’s a big project, but the outcome is a system that can grow with your business.

What’s Your Pick – Monolithic or Microservices?

The choice between Monolithic and Microservices architecture will affect how software is built in your organization.

Monolithic architecture is simpler and best for smaller projects. But as your software grows bigger, Monolithic can get hard to manage.

Microservices turn your software into small independent services which now handle just one thing. This makes Microservices more flexible and easier to update as your software grows. And if you’re leaning towards microservices, tools like Dashbird can be instrumental in your journey. 

Dashbird’s serverless observability and intelligence platform can provide you with the insights and monitoring capabilities needed to manage and optimize your microservices architecture.

Remember, since there are no right answers here, pick the one that makes the most sense to your business goals!