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A Lambda function in a VPC hits an external HTTPS API. Cold starts now take 8+ seconds instead of 800ms. What is the most LIKELY cause?
AVPC-bound Lambdas attach an ENI on cold start; adding VPC integration without optimisation (e.g. shared ENIs / Hyperplane) increases cold-start time
BThe function ran out of disk space
CAll cold starts are 8 seconds and the previous figure was a measurement error
DCloudWatch Logs Insights is slow today
Answer & Solution
Correct answer: A. VPC-bound Lambdas attach an ENI on cold start; adding VPC integration without optimisation (e.g. shared ENIs / Hyperplane) increases cold-start time
VPC-bound Lambdas historically took seconds to set up an ENI per cold container; modern Lambda uses Hyperplane ENIs to amortise this but it's still measurably more than non-VPC. The other options are unrelated.
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