docker

It is absolutely not correct that Larsson did the lion’s share. What he did was implement a Go wrapper for libdevmapper, which exposes a very low-level API. It is the Docker team that implemented devmapper-based container storage, as well as the whole storage plugin system which was now required to support more than one storage method. The original devmapper lib is utterly undocumented and Larsson’s wrapper did not fix that. So getting that feature to work was an all-consuming task and it is the Docker team that did the bulk of it. You can see all this from the early history of the devmapper directory: https://github.com/alexlarsson/docker/commits/a14496ce891f1f...

Each container will have a "fixed-size filesystem", but: - it will be thinly provisioned (i.e. it can be 10G or 100G but still use only a few MB on disk if it's essentially empty, like a sparse file), - it can be grown easily. On the one hand, it's a bit less convenient because you have to care about the disk usage. On the other hand, it's great because a single container can't eat up all your precious disk space (and if you want to run some public/semi-public stuff that's quasi mandatory). If you want to check the current code, you can look here: https://github.com/alexlarsson/docker/tree/device-mapper3