Setting up a server on Hetzner

Overview of the server scripts:

• server/build-nixos-installer-kexec.sh
  From any existing NixOS system, build a NixOS installer kexec image.
• server/start-nixos-installer.sh
  From the Hetzner rescue system, build and run the NixOS installer.
• server/first-time-install.sh <hostname> <disk> [disk ...]
  From the NixOS installer image, wipe the given disks and install NixOS.
• server/install-or-reinstall.sh <hostname> <path/to/mnt>
  From the NixOS installer image, install or reinstall NixOS to the given root filesystem mount, without wiping any disks. Won’t run correctly on the deployed server.

Start the rescue system, then connect over SSH (use ssh -oUserKnownHostsFile=/dev/null) and run the following:

$ git clone https://github.com/servo/ci-runners.git
$ cd ci-runners/server
$ apt update
$ apt install -y zsh
$ ./start-nixos-installer.sh

When you see + kexec -e, kill your SSH session by pressing Enter, ~, ., then reconnect over SSH (use ssh -4 -oUserKnownHostsFile=/dev/null this time) and run the following:

$ git clone https://github.com/servo/ci-runners.git
$ cd ci-runners/server
$ ./first-time-install.sh ci0 /dev/nvme{0,1}n1
$ reboot

Now you can set up the monitor service. Note that rebooting may not be enough to terminate the Hetzner rescue system. If the rescue system is still active, try Reset > Execute an automatic hardware reset in the Hetzner console.