Declarative Operating Systems

A new breed of operating systems adopt declarative configuration management for an interesting hybrid! OS maintenance of long-lived servers remains a challenge for our “mutable” infrastructure.

Although Linux containers greatly abstract away the operating system (OS) and can displace most of configuration management, we now see innovation on the OS side of the equation.

NixOS Linux

NixOS Linux is Linux operating system distribution which uses a declarative model for system configuration, software management, and remote operation. Nix, the package manager, works on Mac OS and Linux, understands package dependencies, and allows multiple versions of software to coexist, making rollback easy. Nix works with the combination build system and Nix package repository named Hydra. There is a public repository of Nix packages, which helps complete dependencies.

An interesting proponent’s opinion = []

I found a Nix/NixOS MeetUp in the SF Bay Area, but the community is small. I very much admire the efforts but had some trouble getting Hydra running on a virtual NixOS box.

Qubes OS Project

Qubes OS is a “reasonably secure operating system” for your laptop or desktop which boots to the Xen hyper-visor and enforces “security by compartmentalization.” Programs run inside Xen VMs for isolation from each other and inside a hardware sandbox. Qubes integrates SaltStack for OS configuration management. I found the Getting Started section to be a great overview of how it works!

The Xen Project has some early integration work with Unikernels and XenServer integrates Docker via APIs to a a CoreOS VM.

I plan to try this in my spare time, but seeing as how this blog entry took over four months to publish, perhaps I’ll hold off for another release.


Guix System Distribution is GNU OS that provides a Guile Scheme API and domain specific language definitions for package management and system configuration.

I found this interesting, but a bit overwhelming to start diving into!

Addendum: Further Investigations

There is more to investigate:

  • Intel’s Clear Linux Project is distribution which attempts to secure and run containers with optimal performance on Intel hardware. Most interesting is their design goal of making the OS stateless. This approach should be contrasted to the minimal host OSs for containers: RancherOS, CoreOS, etc.

  • Docker’s recent acquisition of Unikernel Systems and the micro-kernel movement as a whole (