What Is Aws Lambda?

Recently, Lambda has become popular thanks to AWS, but many folks still use Lambda and serverless interchangeably. In this post, we are going to shed some light on AWS Lambda, including how it ties into serverless architecture, how to create it, and when to use it.

(This tutorial is part of our AWS Guide. Use the right-hand menu to navigate.)

Understanding serverless

To understand what AWS Lambda is, we have to first understand what serverless architecture is all about. Serverless applications in general are applications that don’t require any provisioning of servers for them to run. When you run a serverless application, you get the benefit of not worrying about OS setup, patching, or scaling of servers that you would have to consider when you run your application on a physical server.

Serverless applications or platforms have four characteristics:

1. No server management
2. Flexible scaling
3. No idle capacity
4. High availability

Serverless applications have several components and layers:

• Compute
• API
• Storage
• Interprocess Messaging
• Orchestration

As a cloud provider, AWS offers services that can be used for each of these components that make up a serverless architecture. This is where AWS Lambda comes in.

Describing AWS Lambda

AWS Lambda service is a high-scale, provision-free serverless compute offering based on functions. It is used only for the compute layer of a serverless application. The purpose of AWS Lambda is to build event-driven applications that can be triggered by several events in AWS.

In the case where you have multiple simultaneous events, Lambda simply spins up multiple copies of the function to handle the events. In other words, Lambda can be described as a type of function as a service (FaaS). Three components comprise AWS Lambda:

• A function. This is the actual code that performs the task.
• A configuration. This specifies how your function is executed.
• An event source (optional). This is the event that triggers the function. You can trigger with several AWS services or a third-party service.

When you specify an event source, your function is invoked when an event from that source occurs. The diagram below shows what this looks like: