Activation

nixos-unified provides an .#activate flake app that can be used in place of nixos-rebuild switch (if using NixOS),darwin-rebuild switch (if using nix-darwin) or home-manager switch (if using home-manager)

In addition, it can remotely activate the system over SSH (see further below).

Activating NixOS or nix-darwin configurations

In order to activate a system configuration for the current host ($HOSTNAME), run:

nix run .#activate

# In perSystem
{
    packages.default = self'.packages.activate
}

Activating home configuration

If you are on a non-NixOS Linux (or on macOS but you do not use nix-darwin), you will have a home-manager configuration. Suppose, you have it stored in legacyPackages.homeConfigurations."myuser" (where myuser matches $USER), you can activate that by running:

nix run .#activate $USER@

Per-host home configurations

You may also have separate home configurations for each machine, such as legacyPackages.homeConfigurations."myuser@myhost". These can be activated using:

nix run .#activate $USER@$HOSTNAME

Remote Activation

nixos-unified acts as a lightweight alternative to the various deployment tools such as deploy-rs and colmena. The .#activate app takes the hostname as an argument. If you set the nixos-unified.sshTarget option in your NixOS or nix-darwin configuration, it will run activation over the SSH connection.

Add the following to your configuration – nixosConfigurations.myhost or darwinConfigurations.myhost (depending on the platform):

{
    nixos-unified.sshTarget = "myuser@myhost";
}

Then, you will be able to run the following to deploy to myhost from any machine:

nix run .#activate myhost

Non-goals

Remote activation doesn’t seek to replace other deployment tools, and as such doesn’t provide features like rollbacks. It is meant for simple deployment use cases.