vpsAdminOS

Lightweight host for Linux system containers.


vpsAdminOS is an operating system that serves as a host for container virtualization. It is based on NixOS and not-os.

vpsAdminOS was designed for purposes of vpsFree.cz, a non-profit association that provides virtual servers to its members. We were using OpenVZ Legacy since 2009, but needed to upgrade to a newer kernel, as modern Linux distributions stopped supporting the OpenVZ Legacy kernel.

vpsAdminOS uses:

  • LTS kernel with a mix of out-of-tree patches to improve container experience,
  • runit as an init system,
  • ZFS for storage,
  • our own tools for system container management called osctl,
  • LXC is used to run the containers,
  • AppArmor for additional security,
  • BIRD for network routing.

vpsAdminOS provides means to create and manage system containers, which look and feel as much as a virtual machine as possible. It focuses on user namespace and cgroup management to isolate the containers. All containers are running as unprivileged. One can set resource limits on a single container or groups of containers, allowing for fine-grained control and resource sharing.

osctl is an abstraction on top of LXC, managing system users, LXC homes, cgroups and system containers. vpsAdminOS uses ZFS to store containers and configuration.