nixos-servers/README.md
2024-07-24 21:25:51 +02:00

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# nixos-servers
Nix definitions to configure our servers at home.
## Acknowledgements
- [deploy-rs](https://github.com/serokell/deploy-rs): NixOS deploy tool with rollback functionality
- [disko](https://github.com/nix-community/disko): declarative disk partitioning
- [dns.nix](https://github.com/kirelagin/dns.nix): A Nix DSL for defining DNS zones
- [flake-utils](https://github.com/numtide/flake-utils): Handy utilities to develop Nix flakes
- [nixos-hardware](https://github.com/NixOS/nixos-hardware): Hardware-specific NixOS modules. Doing the heavy lifting for our Raspberry Pi
- [kubenix](https://kubenix.org/): declare and deploy Kubernetes resources using Nix
- [nixhelm](https://github.com/farcaller/nixhelm): Nix-digestible Helm charts
- [sops-nix](https://github.com/Mic92/sops-nix): Sops secret management for Nix
## Installation
### Prerequisites
1. Install the Nix package manager or NixOS ([link](https://nixos.org/download))
2. Enable flake and nix commands ([link](https://nixos.wiki/wiki/Flakes#Enable_flakes_permanently_in_NixOS))
### Bootstrapping
We bootstrap our servers using [nixos-anywhere](https://github.com/nix-community/nixos-anywhere).
This reformats the hard disk of the server and installs a fresh NixOS.
Additionally, it deploys an age identity, which is later used for decrypting secrets.
⚠️ This will wipe your server completely ⚠️
1. Make sure your have a [Secret service](https://www.gnu.org/software/emacs/manual/html_node/auth/Secret-Service-API.html) running (such as Keepassxc) that provides the age identity.
2. Ensure you have root SSH access to the server.
3. Run nixos-anywhere: `nix run '.#bootstrap' <servername> <hostname>`
### Deployment
To deploy all servers at once: `nix run 'nixpkgs#deploy-rs' -- '.#' -k`
To deploy only one server: `nix run 'nixpkgs#deploy-rs' -- -k --targets '.#<host>'`
## Deploying to Kubernetes
To deploy to the Kubernetes cluster, first make sure you have an admin account on the cluster.
You can generate this using `nix run '.#gen-k3s-cert' <username> <servername> ~/.kube`, assuming you have SSH access to the master node.
This puts a private key, signed certificate and a kubeconfig in the kubeconfig directory
We are now ready to deploy to the Kubernetes cluster.
Deployments are done through an experimental Kubernetes feature called [ApplySets](https://kubernetes.io/docs/tasks/manage-kubernetes-objects/declarative-config/#how-to-delete-objects).
Each applyset is responsible for a set number of resources within a namespace.
If the cluster has not been initialized yet, we must bootstrap it first.
Run these deployments:
- `nix run '.#bootstrap-default'`
- `nix run '.#bootstrap-kube-system'`
Now the cluster has been initialized and we can deploy applications.
To explore which applications we can deploy, run `nix flake show`.
Then, for each application, run `nix run '.#<application>'`.
## Known bugs
### Rsync not available during bootstrap
The `rsync` command was removed from recent NixOS ISO which causes nixos-anywhere to fail when copying extra files.
See [this](https://github.com/nix-community/nixos-anywhere/issues/260) issue.
Solution is to execute `nix-env -iA nixos.rsync` on the host.