NixOS on Hetzner Cloud

This article provides a step-by-step guide for setting up a NixOS server on a Hetzner Cloud instance, including partitioning the disk, installing NixOS, and configuring an admin user with SSH access. It also explains how to manage the system configuration via a Git repository by creating a symbolic link from `/etc/nixos/` to a user-controlled repo. The process concludes with instructions for rebuilding the system and verifying the setup.

This is the gist of how to setup a NixOS https://nixos.org/ server on a Hetzner Cloud https://www.hetzner.com/cloud instance with an admin user, ssh access and configuration management via git. 1. Create a Hetzner Cloud instance and click to enter it. 2. Stop the instance top right corner icon . 3. Go to ISO Images . 4. Search for "nixos" and click mount . ISO Images tab of a Hetzner Cloud instance with the NixOS image already mounted https://user-images.githubusercontent.com/30078229/152664634-d580278d-5dd2-468f-b113-f2581d69a5b1.png 5. Start the instance again top right corner icon . 6. Open the console top right corner icon . 7. Get the IP address by executing ip --brief --color address . The address can also be optained from the Hetzner Cloud web interface. lo UNKNOWN 127.0.0.1/8 ::1/128 enp61s0 UP <IPv4 address /24 <IPv6 address /64 8. Download your public ssh key to the machine. If you have a GitHub account you can download it from there. bash mkdir ~/.ssh curl -L https://github.com/<username .keys | tee -a .ssh/authorized keys 9. Log on from your computer on via ssh. bash ssh nixos@<IPv4 address 10. Partition, format and mountthe disk. bash sudo -i Create a GPT partition table. parted /dev/sda -- mklabel msdos Add the root partition. parted /dev/sda -- mkpart primary 1MiB 100% partprobe Format the partition. mkfs.ext4 -L nixos /dev/sda1 Mount root. mount /dev/disk/by-label/nixos /mnt 11. Generate the initial configuration and install. bash nixos-generate-config --root /mnt Set boot device. sed -e 's/^. boot\.loader\.grub\.device. $/ boot.loader.grub.device = "\/dev\/sda";/g' -i /mnt/etc/nixos/configuration.nix Create a directory to manage configurations and import it in the generated config. mkdir /mnt/etc/nixos/configuration/ sed -e 's/\.\/hardware-configuration\.nix/.\/hardware-configuration.nix\n .\/configuration/g' -i /mnt/etc/nixos/configuration.nix 12. Open /mnt/etc/nixos/configuration/default.nix with an editor like vim or nano and paste the following. nix { config, pkgs, ... }: { imports = ./user.nix ; environment.systemPackages = with pkgs; vim wget git htop bottom ; services.openssh.enable = true; } 13. Open /mnt/etc/nixos/configuration/user.nix with an editor and paste the following to create an account with the name admin . Replace the public ssh key with yours . nix { config, pkgs, ... }: { imports = ; users = { users = { admin = { isNormalUser = true; extraGroups = "wheel" ; initialHashedPassword = ""; openssh.authorizedKeys.keys = "ssh-ed25519 AAAA...." ; }; }; }; } 15. Perform installation. bash nixos-install --no-root-passwd 16. Enter the mounted installation and set a password for the admin account. bash nixos-enter --root /mnt passwd admin exit 17. Shut down the machine. bash poweroff 18. Unmount the ISO in the Hetzner Cloud interface and start the machine again. 19. Log on via SSH. bash Remove old host key from install system. ssh-keygen -R <IPv4 address Log in as admin ssh admin@<IPv4 address 20. Turn custom config into repo of admin for convenience bash mkdir repos cp -R /etc/nixos/configuration/ repos/ cd repos/configuration/ Initialize repository with placeholder configuration. git init git config user.name admin git config user.email admin@localhost git add . git commit -m "initial commit" Remove replace old files with symbolic link. sudo rm -r /etc/nixos/configuration/ sudo ln -s /home/admin/repos/configuration/ /etc/nixos/ Test by rebuilding system sudo nixos-rebuild dry-run 21. Have fun and happy hacking