Monolithic vs. Microservices vs. Serverless Architecture
Published: 2024-03-02 09:45:44

When it comes to architectural styles, developers have no shortage of options. There are numerous viable choices and today we will discuss three popular architectural styles. 


## What is Monolithic Architecture?

Monolithic means:  All components of an application are tightly integrated into a single codebase and deployed and deployed as a single unit. Examples of popular companies that have used this include Netflix, Uber, Spotify. 

Remember **MONO**lithic. "MONO" means one. So you can think of Monolithic architecture as **ONE UNIT**. In simple terms, monolithic means having your entire project as a single unit. 

**What are the key characteristics of Monolithic Architecture?**
1. *Single Codebase:* Everything is coded and developed together
2. *Tight Coupling:* Everything is tightly integrated with each other
3. *Centralized Deployment:* The entire application is deployed as a single unit

**How does Monolithic Architecture Perform?**
Let's try and look at some important aspects of performance as it relates to Monolithic Architecture.

1. *Response Times:* Monolithic has poor response times, especially for more complex problems. This is because all the code goes through one application. For smaller applications it works better however as your program becomes more complex and larger it can induce latency problems. 
2. *Scalability:* Monolithic also isn’t able to be scaled well. Because all of the code is closely integrated if one part is changed the rest must also be adjusted to compensate for it. Good to scale vertically, bad to scale horizontally. 
3. *Resource Utilization:* In a Monolithic structure all components share the same resources, such as CPU and memory. It is difficult to efficiently manage resources because of this. The Monolithic style is not very flexible which further hinders it. 

Overall Monolithic Architecture performs better when implementing simple projects or prototypes. However as complexity increases performance decreases. 

**Developing and Deploying Monolithic Architecture**
Another important factor to discuss is how we can develop and deploy a project built using Monolithic Architecture. 

1. *Development:* Easy to develop. Monolith has simple patterns, like for example MVC structure. There is only a single codebase to keep track of and work with. However this also makes this structure less flexible for developers. 
2. *Deployment*: Easy and fast to deploy thanks to the entire application working as a single unit. However for bigger applications it may become more complex and time consuming to deploy. Monolithic is best for simpler and more basic applications. Something like prototypes. 

We can conclude that Monolithic Architecture is best suited for the development and deployment of simpler projects. 

**Operational Considerations for Monolithic Architecture**
Let's analyze some operational considerations which must be taken into account when using Monolithic Architecture. 

1. *Monitoring:* Monitoring an application built with Monolithic architecture requires tracking the overall system performance, resource usage and application help. Tools like Datadog, Prometheus or New Relic can be used to keep track of CPU and memory usage, database performance, and response times. 
2. *Logging:* In Monolithic Architecture centralized logging mechanisms are needed in order to accumulate logs from various parts of the application. Tools like ELK stack or Splunk can be used for this. 
3. *Fault Tolerance:* In Monolithic Architecture Fault Tolerance involves redundancy. For example having multiple servers, implementing retry mechanisms and handling errors centrally. 
4. *Updating/Maintenance:* This requires downtime or a maintenance period. Because the app works as a single unit for any part of it to be updated, the entire application must go down for some time.  

We should keep this in mind when deciding what type of Architecture Style to use. 

**Pros and Cons of Monolithic Architecture**
Now we will take a look at the advantages and disadvantages of Monolithic Architecture.

1. *Pros:* Simplicity: Of the three style, Monolithic is the simplest to comprehend. Performance: Can have lower latency and faster response times for low complexity apps. Ease of Development: Developers have a single unit to develop and maintain. Easier to debug. Ease of Deployment: Entire application is deployed as one unit, making it simpler than Serverless and Microservices
2. *Cons:* Scalability: Challenging to scale as the entire app must be changed to handle new additions. Maintainability: As they grow, Monolithic apps become more complex and difficult to manage. Changes in one part of the code impact the entire system. Fault Isolation: A fault in one service of the application can bring down the entire system. Resource Utilization: All components share the same environment and resources.

## What is Microservices Architecture?
Microservices means: The application is built as a collection of services. These services are all independently deployed and loosely integrated. Examples of popular companies that implement this include Amazon, eBay, SoundCloud. 

Micro **SERVICES**. Services as in plural. Keep in mind that Microservices revolves around working with multiple services. 

**What are the key characteristics of Microservices Architecture?**

1. *Decomposition:* Application broken down to smaller parts
2. *Independence:* Each service is developed and deployed on its own
3. *Loose Coupling:* Microservices are not closely integrated

**How does Microservices Architecture Perform?**
Let's try and look at some important aspects of performance as it relates to Mircoservices Architecture.

1. *Response Times:* Microservices response time depends on the number of services provided. Microservices can induce additional latency because requests need to be routed through various services. 
2. *Scalability*: Microservices architecture can be scaled both horizontally and vertically making it the very flexible. Each microservice can be scaled without impacting other parts of the system because services are developed and deployed independently. 
3. *Resource Utilization:* Because individual sources can be scaled (granular scaling) resources can be efficiently allocated. However, the communication overhead between services and imbalanced workloads can harm its resource utilization. Having services be developed separately allows Microservices to efficiently manage and distribute resources. 

**Developing and Deploying Microservice Architecture**

1. *Development:* Microservices are not fast to be developed. It has less code on average than monolithics architecture but its complexity increases. Microservices require multiple services to be developed. This makes it more complex but also makes it more flexible, meaning different resources can be used by different teams and developers. 

2. *Deployment:* Each service needs to be deployed and managed independently making it more complex. Deploying Microservices means deploying, packaging, and managing multiple services/functions. Because of this microservices deployment is more difficult than monolithic and serverless. 

**Operational Considerations for Microservices Architecture**
Let's analyze some operational considerations which must be taken into account when using Microservices Architecture. 

1. *Monitoring:* Unlike Monolithic Architecture, in Microservices monitoring means tracking the performance of individual services as well as their interactions. Distributed tracing tools like Jaeger or Zipkin help trace requests as they move through multiple services.
2. *Logging*: Each microservice generates its own log. These can then be accumulated using centralized logging solutions. Tools like ELK stack can be used to analyze and collect these logs. 
3. *Fault Tolerance:* The benefit of Microservices is that it promotes fault isolation. Failures can be contained to their respective services so the rest of the application is unaffected. 
4. *Updating/Maintenance:* Microservices makes updates and maintenance more manageable by providing independent deployment of services. However it is still important to manage dependencies between services and also ensure compatibility with other parts of the system. 

**Pros and Cons of Microservices Architecture Architecture**

1. *Pros:* Scalability: Each component can be scaled independently from the rest of the system.  Resource Utilization/Flexibility: Resources can be directed to where they are needed.  Fault Isolation: A fault in one service won’t impact the rest of the system. Easy to isolate faults in code Flexibility: Different teams working on different services can use different tools and frameworks for each service. 
2. *Cons:* Complexity: Have to manage multiple services. Development and deployment is needed for each service. Operational Overhead:  Managing a large number of services needs a robust infrastructure. Deployment pipelines, monitoring and logging all add to operational overhead. Coordination: Coordinating changes across multiple services, ensuring backwards compatibility, and managing dependencies is very difficult.

## What is Serverless Architecture?

Serverless Architecture means: A cloud provider manages the infrastructure needed to run code. Developers focus entirely on writing and deploying functions. Popular examples include Codepen, Figma, AWS.

It is easy to remember how to distinguish Serverless Architecture. As the name suggests, the developer does not need to concern themselves with servers.  

**What are the key characteristics of Serverless Architecture?**
1. *Event Driven:* Functions execute in response to events
2. *No Server Management:* Infrastructure is handled by the cloud provider
4. *Pay-Per-Use:* Serverless platforms only charge users based on the number of executions. 

**How does Serverless Architecture Perform?**
1. *Response Times:* Serverless architecture offers fast response times. In this style it is not needed to manage servers which helps speed up the process. Unlike Monolithic, Serverless is not developed and deployed as a bulk unit so it can support more complex programs. 
2. *Scalability:* Serverless Architecture offers automatic scaling. The scaling is handled by the cloud platform being used. It is highly scalable but may have limitations when it comes to execution and memory. 
3. *Resource Utilization:* Resources are provisioned based on need. They are allocated depending on the actual demand and execution requirements of specific functions. Also has pay per use pricing model making it cost efficient. 

**Developing and Deploying Monolithic Architecture**

1. *Development:*  Serverless architecture has the least code on average of the three however the less the code the greater the complexity. This makes Serverless the most complex of the three. Additionally debugging and testing is more difficult with Serverless Architecture. 
2. *Deployment:* Can deploy individual functions/services without needing to worry about managing the infrastructure. Cloud providers handle scaling, monitoring and maintenance which simplifies the process. 

**Operational Considerations for Serverless Architecture**
1. *Monitoring:* The benefit of Serverless Architecture is that they provide built in monitoring services. Cloud providers like AWS, Google Cloud and Azure provide their own services for monitoring serverless functions. 
2. *Logging:* Similarly cloud providers also offer their own services for logging serverless functions. Logs are generated automatically by these providers. 
3. *Fault Tolerance:* Serverless Architecture similar to Microservices inherently provides fault tolerance. This is because it also has its functions executed in separate environments. Cloud providers automatically handle underlying infrastructure and fault recovery. 
4. *Updating/Maintenance:* Updating and maintaining Serverless Architecture is easier than Monolithic Architecture. Developer’s can update and maintain individual functions without impacting the entire application. 

**Pros and Cons of Serverless Architecture**
1. *Pros:* Scalability: Serverless architecture scales automatically based on demand. Makes for efficient resource utilization. Cost: Pay-per-use protocol means you only pay for resources used during execution. Leads to cost savings. Simplicity: Developers can focus on writing code without worrying about managing infrastructure. Fault Tolerance: Serverless architecture means cloud providers handle infrastructure management, including fault tolerance and scaling.
2. *Cons:* Less Control: Lose control of server hardware, execution, environments and updates. Vendor-Lock-In: Each provider provides its own unique features so it is difficult to switch between them. Debugging and Testing: Hard to replicate the production environment and run successful tests.

## So when should each of these be used?
1. *Monolithic Architecture:* This style is best suited for small to medium sized projects. Monolithic is perfect for projects where development time, expertise, and budget are low. This style is good when an application has low complexity and there is not a need for a lot of flexibility and scalability. It is popular when it comes to prototyping.
2. *Microservices Architecture:* This style is best suited to large-complex projects. This style is best for when projects have multiple teams, tech stacks, evolving requirements, and where scalability is essential. Microservices are useful when continuous development and deployment is needed. If a team has high expertise then they should consider Microservices.
3. *Serverless Architecture:* This style is best suited for event-driven and unpredictable workloads. Such applications can benefit from Serverless Architecture because it scales automatically based on demand. Team expertise should be high if considering Serverless Architecture. Additionally this style is good for stateless applications or functions that can be executed without relying on shared or persistent connections.