Lambda@Edge

5 minutes 5 Questions

Lambda@Edge is an extension of the AWS Lambda service that allows you to execute serverless functions at edge locations closer to your users. This reduces latency and enables you to perform real-time processing of HTTP requests and responses, tailoring the content delivered to users based on factors like location, device type, or authentication status. Lambda@Edge functions are triggered by Amazon CloudFront events and can be used for tasks such as dynamic origin routing, URL rewriting, or custom authentication and authorization.

A Comprehensive Guide to Lambda@Edge

Lambda@Edge is a feature of AWS (Amazon Web Services) Lambda. It enables you to run code closer to the users of your application, which improves performance and user experience.

Why it's important?
Unlike AWS Lambda, which executes functions in response to events in a single AWS region, Lambda@Edge executes functions in response to events generated by Amazon CloudFront. This leads to reduced latency and better performance as it allows the running of code closer to the users' location.

What is it?
Lambda@Edge is essentially a compute service. You can use it to customize content that CloudFront delivers, executing the code in AWS locations globally closer to the user’s location.

How it works?
- AWS CloudFront triggers a function when it receives a request from a viewer - The code runs in an AWS location close to the viewer - The function returns a response to CloudFront, which is then returned to the viewerLambda@Edge scales automatically, running your code in response to CloudFront events.

Exam Tips: Answering Questions on Lambda@Edge
Understanding : Comprehension of Lambda@Edge and its use cases is important for answering exam questions. Understand when to recommend its use, such as improving user experience by reducing latency.
Applying concepts : Be able to describe how to set up Lambda@Edge and how it integrates with CloudFront in the AWS ecosystem.
Time management : Lambda@Edge questions are generally straightforward, so they shouldn’t need too much of your time.
Practice : The more you practice answering Lambda@Edge questions, the more comfortable and quicker you become during the actual exam.

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Question 1

You are deploying a new Lambda@Edge function, but the deployment process fails consistently. After investigation, you discover that the function size is 55MB. What changes should you make to successfully deploy your Lambda@Edge function?

Increase code package size to 60MB Enable multi-region deployments Reduce code package size to 50MB or less Deploy the function from a different AWS Region

Correct Answer: Reduce code package size to 50MB or less

Lambda@Edge deployment restrictions include a maximum unzipped package size of 50MB. Reducing the package size to 50MB or less will solve the issue. The other options don't address the size limitation.

Question 2

You are required to serve different content types (HTML, CSS, Images) from the same Amazon S3 bucket using CloudFront and Lambda@Edge. How should you design the system?

Create multiple CloudFront distributions for each content type At the origin-request event, inspect Accept header and rewrite the URI to fetch the appropriate content file from the S3 bucket Implement a custom application on EC2 instances behind a Load Balancer to serve different content types Use multiple S3 buckets for each content type

Correct Answer: At the origin-request event, inspect Accept header and rewrite the URI to fetch the appropriate content file from the S3 bucket

Lambda@Edge supports rewriting the S3 object's URI at the 'origin-request' event, which can be used to fetch different content types from the same S3 bucket. The other alternatives involve creating multiple infrastructure components or modifying the URI at incorrect events.

Question 3

You are designing a content delivery system that uses CloudFront and Lambda@Edge. The application should process requests from different regions and serve geo-targeted content to users. Which Lambda@Edge event can be most efficiently used to implement this requirement?

origin-request origin-response viewer-response viewer-request

Correct Answer: viewer-request

The 'viewer-request' event in Lambda@Edge allows for decision-based content processing and serves content specific to users' locations. The other events mentioned either happen after the content has been processed or are not valid Lambda@Edge events.

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4 questions (total)