Docker in Docker

For people who already knew this, it might be trivial, but I learned something interesting last week.

I knew you can run pretty much anything in Docker. And I knew Docker with Compose or equivalent tools can be used to run a whole dev environment or something like Testcontainers. I'd even heard at some point that you can potentially run Docker inside Docker, but I either didn't pay attention or had no use for it. And that's what blew my mind when I tried it last week.

As I'm building out my homelab, I set up a full Kubernetes cluster in a devcontainer, and I can easily test new deployments locally. Using my own YAML or Helm—it doesn't matter. Everything is in a container. The whole K8s cluster inside Docker. What? It still blows my mind.

If you want to see how I set it up, check out my Homelab DevContainer configuration on GitHub.