Kubernetes is a consistent management api for linux (so then you don't need to interact with iptables, mount and all that "hard stuff").
I don't think kubernetes is a solution for context of building an image (a rootfs tree into a .tar.gz file).
Unless you are using kaniko which extends the kubernetes api to add the capability of creating images, but that is handled by kaniko itself via the same api.
I was probably unclear. Kubernetes is a good solution for managing containers (obviously). I use it for CI and it works very, very well, though the CI tools still have more features they could add with the integration.
I don't think kubernetes is a solution for context of building an image (a rootfs tree into a .tar.gz file).
Unless you are using kaniko which extends the kubernetes api to add the capability of creating images, but that is handled by kaniko itself via the same api.