Craig Weber

Deploying Go apps on Docker scratch images

NOTE: If you’re here for the TL;DR, skip to the bottom.

A few months ago I built out some monitoring infrastructure at work using Go. I deployed it to ECS (a Docker orchestrator, functionally similar to Kubernetes), and for fun I decided to see how minimal I could make the image. I’ve used Alpine base images before (which weigh in at about 5 MB and usually another 5 MB for a small Go binary), but being that Go advertises itself as requiring only a Linux kernel (most programming languages depend on an interpreter, a VM, and/or system libraries–the latter abstract over kernel functionality and sometimes provide a stable interface to the kernel), I wanted to see how true or practical this was, and I wanted to better understand the things that I was taking for granted by using distros.

As a matter of context, Docker has a special base image called scratch which is empty–an application running on a scratch base image only has access to the kernel (at least to the extent that containers provide isolation).

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