A company hosts a static website in an Amazon S3 bucket, accessed globally via Amazon CloudFront. The Cache-Control max-age header is set to 1 hour, and Maximum TTL is set to 5 minutes. The CloudOps…

Question

Options

• AThe Expires header has been set to 3 hours.
• BCached assets are not expiring in the edge location.
• CCache invalidation is missing in the CloudFront configuration.
• DCache-duration settings conflict with each other.

• A
  2% (1)
• B
  12% (5)
• C
  5% (2)
• D
  80% (33)

Explanation

CloudFront TTL Conflict Explanation

Why D is correct: CloudFront uses the minimum of the Cache-Control max-age header value and the Maximum TTL setting when determining how long to cache an object. Here, max-age is set to 1 hour (3600s), but Maximum TTL is set to 5 minutes (300s) - since Maximum TTL acts as a hard ceiling, CloudFront will only cache objects for 5 minutes, overriding the intended 1-hour duration. This conflict between the two settings causes the unexpected caching behavior.

Why the distractors are wrong:

• A is incorrect because an Expires header set to 3 hours would extend caching duration, not reduce it - and the question describes caching falling short of expectations.
• B is incorrect because assets are expiring (too quickly), not failing to expire - this option describes the opposite problem.
• C is incorrect because cache invalidation removes cached content manually; it doesn't explain a systematic TTL mismatch.

Memory Tip

Think of Maximum TTL as a speed limiter on a highway - no matter how fast (long) your Cache-Control header wants to go, CloudFront will never exceed (or in this case, surpass) the Maximum TTL ceiling. Always ensure both settings are aligned!

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