nixos-servers

Nix definitions to configure our servers at home.

Acknowledgements

• deploy-rs: NixOS deploy tool with rollback functionality
• disko: declarative disk partitioning
• agenix: deployment of encrypted secrets to NixOS machines
• dns.nix: A Nix DSL for defining DNS zones
• microvm.nix: Declarative virtual machine management in NixOS
• flake-utils: Handy utilities to develop Nix flakes
• nixos-hardware: Hardware-specific NixOS modules. Doing the heavy lifting for our Raspberry Pi.

Installation

Prerequisites

1. Install the Nix package manager or NixOS (link)
2. Enable flake and nix commands (link)

Bootstrapping

We bootstrap our physical server using 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 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>

Known bugs

Failed to connect to socket

When deploying a new virtiofs share, the error Failed to connect to '<name>.sock': No such file or directory can occur. This seems to be a bug in microvm.nix and I opened a bug report here. A workaround is to deploy the share without deploy-rs's rollback feature enabled:

nix run nixpkgs#deploy-rs -- -k --targets .#<host> --auto-rollback false --magic-rollback false

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 issue. Solution is to execute nix-env -iA nixos.rsync on the host.