Environment

institute of numerical and applied mathematics (NAM)

• User side:
  • 5 compute servers
  • O(100) client computers
  • 2 login servers
• 2 distributed file systems
  • BeeGFS (compute servers)
  • Ceph (home directories)

• Various VMs (cups, X2go, Kerberos, license servers, Puppet)

• many client computers can (and will) be disconnected

Management

• configuration for the hosts (puppet/foreman used at the moment)

• need configuration for quite different groups of hosts

• want to use Nixos (drop puppet):

  • much cleaner
  • rolling releases possible
  • easier to use reproducible numeric calculations

• Nixops not quite usable (because of disconnected hosts)

General Idea

• Hosts are configured through a custom channel (patched fork of NixPkgs)

• configuration inside the channel (so the client gets the updates)

• Hydra: Periodically checks out the various branches of the repository, builds institute specific packages and the channel.

• periodically run

  nixos-rebuild switch --upgrade

Module Setup

• central module nam/default.nix serves as an entry point for all own modules nam/modules.

• nam.Hostid: identifies the host

• profiles (set of activated modules, like host groups; module itself)

• Mapping Hostid  ↦  list of profiles

secrets

• have credentials inside configs  ↦  need to encrypt

• Use GPG encryption and activate them in the default profile activation script.

• private keys are installed during installation.

Installation (TODO)

• bootstrap (PXE)

• create GPG-key and upload public key

• basic nixos-configuration together with HostID

• hardware-configuration.nix

• set up channel and make a rebuild

User side

need of appropriate (development) environments

• nix-shell

• user-profiles (more stable and easy to switch)

• add packages to ghc/python/.. : script for management of nix-expressions

• how to upgrade?

Open questions

• does our setup make sense?

• global configuration (/etc) or part of Packages?

• user convenience

• dashboard?

Tasks

• actual make automated installation work

• need to create many options for packages (because we configure a lot)

• actual make the configuration modules and profiles

Thank You!