You are mistaken. From https://hub.docker.com/_/docker https://hub.docker.com/_/docker: What is Docker in Docker? Although running Docker inside Docker

You are mistaken. From https://hub.docker.com/_/docker https://hub.docker.com/_/docker: What is Docker in Docker? Although running Docker inside Docker is generally not recommended, there are some legitimate use cases, such as development of Docker itself. ...If you are still convinced that you need Docker-in-Docker and not just access to a container's host Docker server, then read on. This makes it pretty clear that it's a different copy of the docker daemon (which eg. allows you to test changes to docker itself) and specifically says it's different from "just access to a container's host Docker server".