# Kubeadm Cluster Layout (NixOS)

This folder defines role-based NixOS configs for a kubeadm cluster.

## Topology

- Control planes: `cp-1`, `cp-2`, `cp-3`
- Workers: `wk-1`, `wk-2`, `wk-3`

## What this provides

- Shared Kubernetes/node prerequisites in `modules/k8s-common.nix`
- Role-specific settings for control planes and workers
- Host configs for each node in `hosts/`

## Hardware config files

Each host file optionally imports `hosts/hardware/<host>.nix` if present.
Copy each node's generated hardware config into this folder:

```bash
sudo nixos-generate-config
sudo cp /etc/nixos/hardware-configuration.nix ./hosts/hardware/cp-1.nix
```

Repeat for each node (`cp-2`, `cp-3`, `wk-1`, `wk-2`, `wk-3`).

## Deploy approach

Start from one node at a time while experimenting:

```bash
sudo nixos-rebuild switch --flake .#cp-1
```

For remote target-host workflows, use your preferred deploy wrapper later
(`nixos-rebuild --target-host ...` or deploy-rs/colmena).

## Notes

- This does not run `kubeadm init/join` automatically.
- It prepares OS/runtime/kernel prerequisites so kubeadm bootstrapping is clean.