CDN Edge Computing & Edge Functions 3

Question 1

Which isolation technology do most CDN providers (e.g., Cloudflare Workers, Fastly Compute) use instead of containers for edge functions?

Accepted Answer

V8 Isolates

Answer

V8 Isolates provide lightweight, low-overhead sandboxing within a single process, enabling fast cold starts compared to containers or full VMs.

Question 2

A CDN edge function must validate a JWT on every request. Where should the signing secret be stored securely?

Accepted Answer

In a platform-provided secrets or environment variable store

Answer

Secrets must be injected at deploy time via the platform's secure environment variable or secrets management service, never hardcoded in source.

Question 3

What is the purpose of the waitUntil() API available in many edge function runtimes?

Accepted Answer

To allow background async work such as logging to continue after the response is sent to the client

Answer

waitUntil() extends the function's lifetime beyond the response so async tasks like analytics or cache warming can complete without blocking the user.

Question 4

An edge function intercepts a request and must forward a custom header to the origin for tracing. Which step is required?

Accepted Answer

Clone and mutate the Request object, then pass it to fetch()

Answer

Request objects in edge runtimes are immutable, so you must clone them and append the desired headers before passing to fetch().

Question 5

Which metric best measures the real-world performance improvement gained from moving business logic to the edge?

Accepted Answer

Time To First Byte (TTFB) decrease experienced by end users

Answer

TTFB directly reflects how quickly users receive the first byte of a response, making it the clearest indicator that edge processing reduced latency.

(CDN) Content Delivery Network Certification Practice Test

(CDN) Content Delivery Network Certification Practice Test

CDN Edge Computing & Edge Functions 3