[soraminazuki]

For what reason do you "still need Docker?"

With Linux, the only stable base required for Nix to function is the kernel. Nix packages all the required dependencies right down to glibc. Since the Linux kernel famously "doesn't break userspace," any sufficiently new kernel would suffice. Until recently, I've been able to get the latest Nix packages working on an ancient Linux 2.6 kernel. And even the kernel can be managed with Nix if you use NixOS. But Docker can't, so it's no use here.

As for Terraform, I don't see how it's relevant to this discussion. Nix-based SSH deployment tools can replace some of its functionality, so perhaps that's what you're talking about?