[Nix-dev] Proposal: Standard installation procedure

[Eelco Dolstra]

Hi,

On 16/10/14 13:00, Ertugrul Söylemez wrote:

> The basic idea is this:  To build a system, you use a standard function
> from Nixpkgs and pass it a configuration module.  The result is a
> derivation that represents a complete self-contained system.

How does that differ from how NixOS is currently implemented? You can do:

  $ nix-build '<nixpkgs/nixos>' -A system

which gives you a complete system in ./result, where e.g. ./result/init is the
stage 2 init script that runs the activation script and invokes systemd.

Programs like nixos-rebuild, nixos-install, nixos-container and even NixOps are
really just wrappers around this (except that they add various levels of
provisioning).

> In other words a container-based NixOS system is really just a Nix
> store, nothing more.  It doesn't need to contain any additional files or
> directories and building it does not require us to understand the
> complexity of nixos-install, because it will all be moved to the system
> initialisation phase.

I don't think nixos-install is that complex. Almost all of the initialisation it
does in the target file system is to make nix-build work in the chroot. The
NixOS initialisation is done by the activation script.

Check out "nixos-container create" - it does almost no initialisation of the
container file system, since everything is done by the activation script during
the first boot of the container.

-- 
Eelco Dolstra | LogicBlox, Inc. | http://nixos.org/~eelco/