[vesak]

I'd like to bring up another sort-of alternative: http://habitat.sh

It's not exactly in the same space as Nix, but not very far from it, either. In Habitat, you use a language that felt to me quite similar to Arch Linux's PKGBUILDs, but extended with container-specific things like service ports etc. Habitat outputs containers that can be started in various orchestration technologies, like Kubernetes or Mesos/Marathon.

[ungzd]

It's interesting and very similar to Nix, but I still didn't figure out purpose of it, especially why it heavily uses Docker. Many people use Docker for the same functionality that Nix provides: bundling application with its dependencies, not for isolating groups of processes from each other.

[vesak]

Docker images is one of the supported formats when exporting packages. Others at the moment are aci, mesos and tarball.