Exam AWS Certified Solutions Architect - Associate SAA-C03 topic 1 question 881 discussion

AE. By default, each file automatically expires after 24 hours, but you can change the default behavior in two ways: 1. To change the cache duration for all files that match the same path pattern, you can change the CloudFront settings for Minimum TTL, Maximum TTL, and Default TTL for a cache behavior. 2. To change the cache duration for an individual file, you can configure your origin to add a Cache-Control header with the max-age or s-maxage directive, or an Expires header to the file. https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/Expiration.html#expiration-individual-objects

You simply can't have A and E in the same approach: "Default TTL applies only when your origin does not add HTTP headers such as Cache-Control max-age, Cache-Control s-maxage, or Expires to objects." C - Cache-Control private directive specifies that the response is intended for a single user and should not be cached by shared caches - it can still be cached, but only on a client device. This combination of steps would provide the best solution for the case. https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/distribution-web-values-specify.html#DownloadDistValuesDefaultTTL

A-C, Because A-E is not possible following this link: https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/distribution-web-values-specify.html#DownloadDistValuesDefaultTTL "Default TTL applies only when your origin does not add HTTP headers such as Cache-Control max-age, Cache-Control s-maxage, or Expires to objects."

If the content still keep client's cache in 24h, its wrong (answer E)

If your minimum TTL is greater than 0, CloudFront uses the cache policy’s minimum TTL, even if the Cache-Control: no-cache, no-store, and/or private directives are present in the origin headers. https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/Expiration.html

"However, the company also wants to ensure that stale content is not served for more than a few minutes after a deployment." After a deployment

Answer (AC) Per table on URL https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/Expiration.html#expiration-individual-objects answer E is incorrect because if we will change cache-control max-age to 24h it will means that customer browser will cache web for 24h and customer want to be sure that it will be not longer then few min. Expires header (answer D) from my understanding can be used only on full folder of web not as lambda function which will reply to customer reqeusts. We are setting Default TTL for CloudFront (answer A) not on S3 (answer B) and it will say CloudFront to cache web for 2min.

https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/Expiration.html#expiration-individual-objects https://stackoverflow.com/questions/43343759/confused-with-minimum-maximum-and-default-ttl-in-cloudfront

Since it don’t want to cache more than a minute, A cannot be an answer

Answer is AE , C would only be on the user browser and would not cache to the cloud front and would be useless

Add a Cache-Control Private Directive to Objects in Amazon S3 (Option C): By setting the Cache-Control header to private for objects in the S3 bucket, you control caching behavior. The private directive indicates that the content is intended for a single user and should not be cached by intermediate proxies or CDNs. This helps prevent stale content from being served to multiple users. Additionally, consider using other Cache-Control directives (e.g., max-age, no-cache, no-store) as needed.