I was guessing build times from my laptop. A six-cent spot instance proved me wrong.

Mon, 16 Mar 2026 10:00:00 -0600

I needed to know how fast a 16GB Docker image builds on Graviton. The image is a Docling container — document intelligence, heavy Python dependencies, big model downloads. I was sizing a self-hosted runner for CI and needed real numbers: build duration, peak memory, CPU profile. The numbers would determine whether I could get away with an r6g.large or needed to step up to an xlarge.

I did what everyone does first. I ran the build on my laptop.

Graviton on ferkakta.dev

I was guessing build times from my laptop. A six-cent spot instance proved me wrong.