Future-proof software development with the Azure Serverless Modulith
Tags: serverless, azure, azurefunctions, eventdriven
Published: 2024-06-10 20:39:36

When developing modern software solutions, architects and developers are faced with the challenge of designing systems that are scalable, maintainable and cost-effective. Traditionally, monolithic architectures offer the advantage of simplicity in development and deployment, but often reach their limits in terms of scalability and maintainability. Microservices solve many of these problems, but bring their own challenges such as increased complexity and difficult coordination.

## What is a monolith?
Monolithic architectures are characterized by the fact that all components of an application are closely linked and provided as a single unit. This can simplify development and deployment, but leads to difficulties in scalability and maintainability as the application grows.

## Modularity in the monolith
Modularity allows a monolith to be divided into clearly delineated modules. These modules can be developed and maintained independently of each other, which improves maintainability and enables more targeted scaling of individual modules.

## The Serverless Modulith: an innovative solution
The Serverless Modulith combines the advantages of modularity with the strengths of serverless computing. Each module is provided as an independent serverless function, which offers several advantages:

**Scalability**: each module can be scaled independently, based on specific requirements and load.
**Cost efficiency**: Thanks to usage-based billing, companies only pay for the computing time they actually use.
**Reduced complexity**: Developers can focus on the business logic as the cloud provider manages the infrastructure.
**Faster time-to-market**: Individual modules can be developed and deployed independently, which speeds up the introduction of new functions.

## Architecture overview
A serverless modulith with Azure Functions consists of a structured and modularized application. Each functional unit is provided as an independent serverless function. Here is an example of such a structure:

**API Gateway**: An Azure API Management Gateway serves as a central point for all incoming requests and forwards them to the corresponding Azure Functions. It handles authentication, authorization and rate limiting.
**Logic**: Each module of the application is implemented as a separate Azure Function. These modules can perform tasks such as data processing, API endpoints, background tasks or event-driven processes.
**Communication**: The modules communicate with each other via Azure Service Bus or Azure Event Grid to enable loose coupling and asynchronous processing.
**Database**: Azure Cosmos DB, Azure SQL Database or Azure Table Storage can be used as central databases that the individual modules access.


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/s1z67hwkcc76avoftuga.jpg)

## Challenges when using serverless moduliths
Although the serverless modulith offers many advantages, there are also challenges that need to be considered:

### Vendor lock-in
When using cloud-based serverless services such as Azure Functions, AWS Lambda or Google Cloud Functions, a certain degree of vendor lock-in is unavoidable. Architecture and implementation depend heavily on the specific services and APIs of the chosen cloud provider. However, it is important to emphasize that vendor lock-in is not inherently bad. The use of standard software solutions such as Office 365 or Teams also leads to vendor lock-in. It is crucial that companies carefully consider whether this dependency could be problematic in the future.

One approach to minimizing risk is to use hybrid solutions such as Docker containers in a serverless environment on Azure. These containers can be operated in different cloud environments or even on-premises, which increases flexibility and reduces the risk of lock-in.

### Cold starts
Cold starts are another common problem with serverless architectures. These occur when functions are reactivated after a period of inactivity and cause additional latency. Modern hosting plans such as the Azure Functions Premium Plan or AWS Lambda Provisioned Concurrency offer solutions that significantly reduce this problem. These plans make it possible to keep a certain number of instances warm, which minimizes request latency and improves response times.

## Conclusion
The Serverless Modulith is an innovative solution for modern software development requirements. It combines the advantages of modularity and serverless computing and enables companies to work more flexibly, cost-effectively and scalably. At the same time, the complexity of infrastructure management is reduced. Despite the challenges, such as vendor lock-in and cold starts, the advantages outweigh the disadvantages, especially if suitable strategies are implemented to overcome these challenges.

## Ressources:
- [Azure Serverless Modulith](https://www.florian-lenz.io/blog/serverless-modular-monolithen-der-wegbereiter-fuer-agile-entwicklungen)
- [Azure Serverless Modulith Video](https://www.youtube.com/watch?v=5kbJSH-dKKo)