As my comment implies, nix and nixpkgs can do what `linuxkit` does (in terms of image building, at least) but better and in a more powerful manner.
I can create nix derivations that look like a linuxkit yaml, but instead of having a bunch of opaque sha256 hashes to some container in them, it has symbolic references to packages that are defined in my nixpkgs repository. This nixpkgs repository includes package definitions for basically everything in a distribution. From it, out of the box, you can issue single commands to build: VM images, container images, images ready to deploy on GCE/AWS/Azure, all from a single set of package definitions.
This means I can issue a single command that will output a VM image (or a container) that includes the exact revisions of all of my software, down to the kernel options and compiler flags. It makes it trivial to take in patches for critical components and rebuild a base image. No cloning extra repos. No build, container build, push, grab sha256, copy sha256 into a yaml file. Just specify the patch, hit rebuild, done.
You can do this for VM images, specifying the total system configuration - how you want etcd/kubelet/etc running, for example. One command and you have a bootable Azure VHD. You can then use the same tree, or maybe a different branch, and declaratively(!), very minimally [1] build the most optimal container images that you then have deployed to Kubernetes or wherever.
And you can be sure that you can build this exact configuration in 1 year, 2 years, 3 years, etc, due to how Nix works.
I hope I've done a somewhat okay job of explaining this. I'm trying to take some time and write a "container oriented look at why Nix is cool" guide soon too.
I'm not that much in devops/containers guy, bit I'm not aware about linuxkit alternative in the Linux world, care to elaborate?