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Comment by eyjafjallajokul | Hacker News Reader

Source?

https://aws.amazon.com/blogs/aws/firecracker-lightweight-vir... says

> Battle-Tested – Firecracker has been battled-tested and is already powering multiple high-volume AWS services including AWS Lambda and AWS Fargate.

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Counterpoint: https://justingarrison.com/blog/2024-02-08-fargate-is-not-fi...

And also, you’ll notice that Fargate takes minutes to launch while Lambda takes a second or less. You’re waiting on AWS to launch a EC2 with your config and pull your containers into it.

(that article matches things I heard from Amazon when I asked why my stuff is slow)

Confirming, I worked directly on fargate.

Fargate does not use firecracker. It was used for some internal workloads but was being migrated off at the end of 2025.

I can't tell you why Fargate is so slow, but the reason Lambda containers are so fast is because it doesn't actually load the image. It loads a manifest of the layers and the files in each, and then each file is loaded on-demand from a multi-tier cache. 90% of the image is never loaded, and 90% of the remainder is served from local cache. It's a pretty cool architecture.

Container pulls are slow. Lambda starts fast as it's not unpacking your container to a local disk on every start.

It was true a long time ago for some particular cases, but is not true since quite some years now.

the doc is out of date

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