AWS Cloudfront Interview Questions and Answers

TOP 30+ AWS Cloudfront Interview Questions and Answers

If you’re looking for  Frequently asked AWS Cloudfront Interview Questions for Experienced or Freshers, you are in the right place.

There are a lot of opportunities from many reputed companies in the world. Get prepared for your AWS Cloudfront Interview Questions with these top questions and answers.

AWS Cloudfront Interview Questions

Q1: What is AWS CloudFront?

Q2: What is the Content Delivery Network (CDN)?

Q3: How does CDN or AWS Cloudfront work?

Q4. What are the benefits of AWS CloudFront?

Q5. What are the features of CloudFront?

Q6. What are the Uses AWS CloudFront? 

Q7: What happens in CDN, if files are not present in cache to deliver to the user?

Q8. What are the use cases of the AWS Cloudfront?

Q9. How to redirect custom domain path to Cloudfront AWS?

Q10. When to use Amazon Cloudfront?

Q11. Can a Single web server be used to implement CDN at amazon?

Q12. How can we disable Cache for CloudFront?

Q13. How CloudFront events trigger a Lambda Function?

Q14. What is CloudFront Functions?

Q15. What are the use cases of using CloudFront Functions?

Q16. Can we Improve the time latency if we use a CDN in front of S3? What will be the degree of improvement in time latency and end-user experience in terms of time in milliseconds?

Q17. Can I Use CloudFront for dynamic content?

Q18. We are a company creating content and distributing it as “download file” from our website for our end users. Can we use CloudFront in this case ?

Q19. What can I do with Amazon CloudFront?

Q20. How does Amazon CloudFront provide higher performance?

Q21. How does Amazon CloudFront lower my costs to distribute content over the Internet?

Q22. How is Amazon CloudFront different from Amazon S3?

Q23. How is Amazon CloudFront different from traditional content delivery solutions?

Q24. What types of content does Amazon CloudFront support?

Q25. Does Amazon CloudFront offer a Service Level Agreement (SLA)?

Q26. What is CloudFront Regional Edge Cache?

Q27. Is Amazon CloudFront PCI compliant?

Q28. Is Amazon CloudFront HIPAA eligible?

Q29. Is Amazon CloudFront SOC compliant?

Q30. What are the key benefits of using HTTP/3 with Amazon CloudFront?

 

Q1: What is AWS CloudFront?

Amazon CloudFront is an Amazon Web Services content delivery network. Easily cached content, like web videos or other hefty files, can be accessed more quickly with content delivery networks.

CloudFront is a Content Delivery Network (CDN). Using Amazon S3 buckets, it retrieves data and distributes it to several datacenters. Edge locations are a network of data centres that deliver the data. In order to achieve the lowest possible latency, low network traffic, and quick access to data, users are routed to their nearest edge location when they request information.

 

Q2: What is the Content Delivery Network (CDN)?

Content delivery network (CDN) is a network of distributed servers that delivers websites and diverse types of internet material to user-selected geographic locations, as well as a content delivery server.

 

Q3: How does CDN or AWS Cloudfront work?

The major task of CDN is to create caches. Data in a cache is often stored in rapid access hardware such as RAM, which results in faster performance and lower costs at scale.

As an example, here’s what occurs when a user tries to view your content after successfully configuring Cloudfront:

Users who visit your website or use your application expect to download files such as multimedia or HTML files.

As a result of DNS, requests are routed to the Cloudfront POP (edge location) that best serves them.

Cloudfront verifies its cache for the requested file in the POP. In this case, Cloudfront sends the files to the user.

 

Q4. What are the benefits of AWS CloudFront?

  1. Security to the Content – It is a highlt content dilevery network which has each network and application level protection.It defends our applications from a lot of refined threats and DDoS attacks.
  2. Integrating Network – This construct on the increasing international AWS infrastructure.It helps the applications by delivering availability, scalibility and performance for everyone.
  3. Great Performance – It directly connects with many end users ISPs and the AWS backbone network to accelerate the delivery of the content end to end.
  4. Economical – By this the users pays just for the information transfer and requests accustomated delivery content to the customers.

 

Q5. What are the features of CloudFront?

  1. Fast
  2. Simple
  3. Cost-effective
  4. Elastic
  5. Reliable
  6. Global

 

Q6. What are the Uses AWS CloudFront? 

  1. Static Quality Caching helps in speding up the process of delivery of the content.
  2. Live and On-Demand Video Streaming helps in streaming the media with Amazon CloudFront.
  3. Security and DDoS Protection defends the layer of DDoS mitigation and also AWS WAF for seven layers protection.
  4. Dynamic and Customized Content improves the performance, responsibility, and updates dynamic parts of the application.
  5. API Acceleration accelerates the API calls.
  6. Software Distribution globally distributes and transfer software updates.

 

Q7: What happens in CDN, if files are not present in cache to deliver to the user?

It does the following if the files are not in the cache:

Cloudfront verifies the request against your distribution’s parameters and sends the files request to the appropriate origin server for the file type – for example, your Amazon S3 bucket for image files and your HTTP server for HTML files.

The files are returned to the edge location by the origin servers.

Cloudfront starts forwarding files to the user as soon as the first byte arrives from the origin.

Cloudfront additionally saves the files in the edge location’s cache for the next time they’re requested.

 

Q8. What are the use cases of the AWS Cloudfront?

Below are the useful use cases of the AWS Cloudfront:

Live Streaming: Cloudfront is built for high-volume requests and is geared for live streaming. It can accommodate millions of people requesting the same manifest or video segments at the same time while maintaining a low-latency stream. It may be set up to produce streams with a camera device screen latency of less than three seconds and synchronisation of less than one second. It’s completely integrated with AWS Elemental MediaStore, as well as AWS Elemental MediaLive for video encoding and AWS Elemental MediaConnect for video transcoding, and an optimised low-latency origin server developed for live streaming.

On-Demand Video: You can use Cloudfront to provide massive, long-tail content catalogues to people all around the world. Cloudfront is a completely integrated, simple-to-use content delivery network (CDN) for both simple and complex video production workflows. It integrates with AWS Media Services such as AWS Elemental MediaPackage and AWS Elemental MediaConvert.

Q9. How to redirect custom domain path to Cloudfront AWS?

We can use CloudFront Functions to redirect at the edge if we need to.

There are two options if we wish to rewrite a URL:

  1. Edit the Origin path field on your origin in the CloudFront console to /path if users want a request to CloudFront of example.com/foo to fetch your-origin.com/path/foo from your origin. 
  2. Can utilise CloudFront functions to rewrite the request.urias needed if the user wants a conditional URL rewrite

Q10. When to use Amazon Cloudfront?

CloudFront is a CDN that proxies and caches web data at edge locations as close to users as possible.This data is served by CloudFront that may or may not come from S3, as it is more optimized for delivery speed and the bandwidth costs more. If tht user is localized we cant see too much difference working with S3 or CloudFront.

Q11. Can a Single web server be used to implement CDN at amazon?

Yes we can use a single web server for implementing CDN at amazon as we do not mandate use of minimum use of the origin in terms of numbers of EC2 instances.

Q12. How can we disable Cache for CloudFront?

We can disable cache for cloudfront by inputing the value for :

Minimum TTL – helps in specifying the minimum amount of time we want the objects to stay in CloudFront caches before cloudfront sends another request to our origin for determining if the object is updated.

Maximum TTL – helps in specifying the maximum time we want the objects to stay in CloudFront caches before cloudfront sends another request to our origin for determining if the object is updated.

Default TTL – helps in specifying the default time we want the objects to stay in CloudFront caches before cloudfront sends another request to our origin for determining if the object is updated.

Q13. How CloudFront events trigger a Lambda Function?

You can add up to four triggers (associations) for each cache behaviour in a CloudFront distribution that cause a Lambda function to activate when specified CloudFront events occur. As illustrated in the diagram, CloudFront triggers can be based on one of four CloudFront events.

The following CloudFront events can be used to trigger Lambda@Edge functions:

Viewer Request : When CloudFront receives a request from a viewer, the function is called before it checks to verify if the requested object is in the CloudFront cache.

Origin Request : When CloudFront forwards a request to the user’s origin, this function is called. The function does not run if the requested object is already in the CloudFront cache.

Origin Response : After CloudFront receives a response from the origin, the function runs before it caches the item in the response. It’s worth noting that the function runs even if the origin returns an error.

In the following scenarios, the function does not run:

  • When the requested file is not expired and is in the CloudFront cache.
  • When a response is generated by a function that was called in response to an origin request event.

Viewer Response : Before returning the requested file to the viewer, the function runs. It’s worth noting that the function executes whether or not the file is already in the CloudFront cache.

In the following scenarios, the function does not execute:

  • When the origin returns a 400 or higher HTTP status code.
  • When a custom error page is returned.
  • When the response is generated from a function which was triggered by a viewer request event.
  • When CloudFront redirects an HTTP request to HTTPS automatically.

Q14. What is CloudFront Functions?

Users can develop lightweight JavaScript functions for high-scale, latency-sensitive CDN customizations using CloudFront Functions in Amazon CloudFront. Such functions can handle CloudFront requests and responses, conduct basic authentication and authorization, and produce HTTP responses at the edge, among other things. The CloudFront Functions runtime environment is highly secure and has submillisecond startup times. It scales instantly to accommodate millions of requests per second. Because CloudFront Functions is a built-in component of CloudFront, you can build, test, and deploy your code entirely within the platform.

Q15. What are the use cases of using CloudFront Functions?

For use cases like the following, CloudFront Functions is excellent for lightweight, short-running functions:

Cache key normalisation – You could optimise your cache hit ratio by transforming HTTP request information (headers, query strings, cookies, and even the URL path) into an appropriate cache key.

Header manipulation – In the request or response, you can insert, edit, or delete HTTP headers. Every request, for example, could include a True-Client-IP header.

URL rewrites or redirects – You can rewrite all requests from one path to another or redirect users to other pages depending on information in the request.

Request authorisation – You can analyse authorization headers or other request information to verify hashed authorization tokens, like JSON web tokens (JWT).

Q16. Can we Improve the time latency if we use a CDN in front of S3? What will be the degree of improvement in time latency and end-user experience in terms of time in milliseconds?

Yes, time latency can be improved by using CDN in front of S3. It will depend on the location/geographical region the content is accessed from. There are a number of tools available to test this improvement. For example you can use https://www.webpagetest.org/ to compare two urls in terms of time latency from different geographical locations.

Q17. Can I Use CloudFront for dynamic content?

Yes, CloudFront can be used for dynamic content. You can include query string parameters to help customise your web pages for each viewer. You can also configure multiple cache behaviours for your download distributions based on URL patterns on your website.

Q18. We are a company creating content and distributing it as “download file” from our website for our end users. Can we use CloudFront in this case ?

Yes you can use CloudFront download distribution, where you can have content downloads going through edge locations for minimal download latency.

Q19. What can I do with Amazon CloudFront?

Amazon CloudFront provides a simple API that lets you:

Distribute content with low latency and high data transfer rates by serving requests using a network of edge locations around the world.

Get started without negotiating contracts and minimum commitments.

Q20. How does Amazon CloudFront provide higher performance?

Amazon CloudFront employs a global network of edge locations and regional edge caches that cache copies of your content close to your viewers. Amazon CloudFront ensures that end-user requests are served by the closest edge location. As a result, viewer requests travel a short distance, improving performance for your viewers. For files not cached at the edge locations and the regional edge caches, Amazon CloudFront keeps persistent connections with your origin servers so that those files can be fetched from the origin servers as quickly as possible. Finally, Amazon CloudFront uses additional optimizations – e.g. wider TCP initial congestion window – to provide higher performance while delivering your content to viewers.

 

Q21. How does Amazon CloudFront lower my costs to distribute content over the Internet?

Like other AWS services, Amazon CloudFront has no minimum commitments and charges you only for what you use. Compared to self-hosting, Amazon CloudFront spares you from the expense and complexity of operating a network of cache servers in multiple sites across the internet and eliminates the need to over-provision capacity in order to serve potential spikes in traffic. Amazon CloudFront also uses techniques such as collapsing simultaneous viewer requests at an edge location for the same file into a single request to your origin server. This reduces the load on your origin servers reducing the need to scale your origin infrastructure, which can bring you further cost savings.

 

Q22. How is Amazon CloudFront different from Amazon S3?

Amazon CloudFront is a good choice for distribution of frequently accessed static content that benefits from edge delivery—like popular website images, videos, media files or software downloads.

 

Q23. How is Amazon CloudFront different from traditional content delivery solutions?

Amazon CloudFront lets you quickly obtain the benefits of high performance content delivery without negotiated contracts or high prices. Amazon CloudFront gives all developers access to inexpensive, pay-as-you-go pricing – with a self-service model. Developers also benefit from tight integration with other Amazon Web Services. The solution is simple to use with Amazon S3, Amazon EC2, and Elastic Load Balancing as origin servers, giving developers a powerful combination of durable storage and high performance delivery. Amazon CloudFront also integrates with Amazon Route 53 and AWS CloudFormation for further performance benefits and ease of configuration.

 

Q24. What types of content does Amazon CloudFront support?

Amazon CloudFront supports content that can be sent using the HTTP or WebSocket protocols. This includes dynamic web pages and applications, such as HTML or PHP pages or WebSocket-based applications, and any popular static files that are a part of your web application, such as website images, audio, video, media files or software downloads. Amazon CloudFront also supports delivery of live or on-demand media streaming over HTTP.

 

Q25. Does Amazon CloudFront offer a Service Level Agreement (SLA)?

Yes. The Amazon CloudFront SLA provides for a service credit if a customer’s monthly uptime percentage is below our service commitment in any billing cycle. 

 

Q26. What is CloudFront Regional Edge Cache?

CloudFront delivers your content through a worldwide network of data centers called edge locations. The regional edge caches are located between your origin web server and the global edge locations that serve content directly to your viewers. This helps improve performance for your viewers while lowering the operational burden and cost of scaling your origin resources.

 

Q27. Is Amazon CloudFront PCI compliant?

Yes, Amazon CloudFront is included in the set of services that are compliant with the Payment Card Industry Data Security Standard (PCI DSS) Merchant Level 1, the highest level of compliance for service providers.

 

Q28. Is Amazon CloudFront HIPAA eligible?

Yes, AWS has expanded its HIPAA compliance program to include Amazon CloudFront as a HIPAA eligible service. If you have an executed Business Associate Agreement (BAA) with AWS, you can use Amazon CloudFront to accelerate the delivery of protected health information (PHI).

 

Q29. Is Amazon CloudFront SOC compliant?

Yes, Amazon CloudFront is compliant with SOC (System & Organization Control) measures. SOC Reports are independent third-party examination reports that demonstrate how AWS achieves key compliance controls and objectives. 

 

Q30. What are the key benefits of using HTTP/3 with Amazon CloudFront?

HTTP/3 enables this as it offers several performance improvements over previous HTTP versions:

Faster and reliable connections – CloudFront uses 1-RTT for TLS handshake for HTTP/3 reducing the connection establishment time and a corresponding reduction in handshake failure compared to previous HTTP versions.

Better web performance – CloudFront’s HTTP/3 implementation supports client-side connection migrations, allowing client applications to recover from poor connections with minimal interruptions. Unlike TCP, QUIC is not lossless making it better suited for congested networks with high packet loss. Also, QUIC allows faster re-connections during Wifi or cellular handoffs.

Security – HTTP/3 offers more comprehensive security compared to previous versions of HTTP by encrypting packets exchanged during TLS handshakes. This makes inspection by middleboxes harder providing additional privacy, and reducing man-in-the-middle attacks. CloudFront’s HTTP/3 support is built on top of s2n-quic and Rust, both with a strong emphasis on efficiency and performance. 

 

Good Luck !! Happy Learning !!

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