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status: draft
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# NixOps4-based Installation Process

This documents explains how NixOps4 could be leveraged to provide a smooth installation experience for a simple, monolithic deployment.

It does not go into detail about the way Nix Panel hooks into this, or whether Nix Panel manages the same NixOps4 deployment that also contains the infrastructure; a single NixOps4 deployment could provide a nice simplification in the early stages of the project.

## Components

Required for the setup steps in this document:

- `nixops4`: generic deployment tool using Nix
- `landscaper.iso`: installation image that bootstraps a completely new and independent Fedi cluster - a NixOS installer with a handful of extra definitions (@roberth: easy)
- `nixops4-modules-ssh-keypair`: NixOps4 resource provider that generates keys
- `nixops4-pxe-nbp`: NixOps4 resource provider that inserts an NBP image into a (local) PXE server configuration
- `nixops4-modules-ssh`: A module that calls `ssh` using `nixops4-resources-local`
- `nixops4-resources-local`: A module that can create files and call commands locally (prototyped)
- `nixops4-modules-nixos`: A module that calls `nixos-rebuild switch --target-host` or implements similar functionality

Expected needs:

- `nixops4-resources-proxmox`
- A resource provider that talks to a DNS server's API

## Steps

### 1. `landscaper` setup

1. connect your first server into the network

2. boot `landscaper.iso` from a usb stick, and install NixOS onto this server we'll call `landscaper`

`landscaper.iso` is  a slightly customized NixOS installer that includes the `landscaper` NixOS module
     in the default config that it generates
  - mvp: copy and import the landscaper module by hand into the normal NixOS live system

The `landscaper` module contains 
    - nixops4 (mvp and initial setup)
    - a nixops4 service (if/when nix-panel is capable of managing the infra)
    - a tftp server

The NixOS installer puts the template NixOps4 expression in `/root/fediversity-network`

### 2. Add a proxmox host

1. - add a MAC address and IP address to the `proxmoxMACs` option (or similar)
    - this automatically declares resources that will set up the new server
      - `installation_host_key`: a temporary SSH host key pair
      - `installation_pxe_nbp`: an entry in `landscaper`'s PXE server, referring to/including a kernel and initrd that run disko and performs a NixOS installation on the server disk(s)
      - `ssh_host_public_key`: a resource that waits for SSH to come up, logs in to replace the host key and sends the returns the new public key as its resource output
      - `nixos`: a resource that `nix copy`-es a NixOS toplevel, then updates the system profile and activates it

      - unknown: built-in services like Nix-panel, perhaps depending on the number of `proxmoxMACs`
2. `nixops apply`
    - this starts to create resources,
    - up to the point that `ssh_host_public_key` waits for the server to boot
3. turn on the server
4. wait for `nixops apply` to complete

## Notes

Unknown: add to step 2 or step 3 (new), depending on the amount of shared infra:
 - resources for certain objects in the proxmox api
    - this creates nixpanel, and shared infrastructure