[jakewins]

We use it a bit, mainly as a side-effect of infrastructure. For instance, our CI runs each job in a container; the spec for the container is checked into source control. That way its easy to add new software in CI, just change the Dockerfile in the project repo. Also easy to run CI jobs locally for debugging.

Then some of our integration tests themselves use Docker, for various things. And at that point, docker in docker comes in handy.

We just run regular docker-in-docker though, which is indeed a very leaky abstraction, lots of pitfalls.