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Why use a microservices approach?

Disclaimer: this documentation is a work in progress. Feel free to open an issue on Swarmion

Swarmion is primarily a microservices framework. When building Serverless applications, relying on the traditional monolithic approach becomes limited.

What is a monolith?​

A Monolith is the traditional way of building and deploying web applications. The principle is to put all the code and business logic in a single deployment unit. It can be deployed in many different ways, but all the code needs to be shipped at once.

Its main advantages are:

  • the deployment unit: there can only be one live version of the code
  • the easy start: many existing frameworks

While this is a completely valid approach, it has some drawbacks that can make it impractical as the codebase grows and so does the number of people involved.

Using a monolithic approach in Serverless applications​

There are mainly two way to have a monolithic approach for Serverless applications:

  • the mono-lambda approach: using a single function to deploy all your business logic
  • the mono-stack approach: provisioning all the resources and business logic of your application in a single stack (mono-stack approach)

Know issues with monoliths in Serverless applications​

The main drawbacks in :

  • it can become hard to maintain the codebase coherence as it grows
  • processes cannot scale as the codebase grows
    • all parts of the code need to be run at every change, even th
    • Hard limits: it is not possible to provision an unlimited number of resources at the same time. AWS CloudFormation, for example, has a hard limit of 500 resources per stack. It may seem a lot but it means that ignoring this constraint may mean a costly refactoring in the future.

What are microservices?​

In order to tackle the monolith drawbacks, the microservices approach introduces many deployment units, each one containing a small part of our application code.

References​

  • Building microservices, Sam Newman