sops-nix (in the nixos flake) derives each host's age decryption key
from its own /etc/ssh/ssh_host_ed25519_key at activation time, which
runs before systemd would otherwise generate that key on first boot
(sshd-keygen is a plain systemd service gated behind multi-user.target;
activation scripts run earlier). Without pre-seeding, secrets --
including the login password -- fail to decrypt on a fresh install's
very first boot.
- scripts/prepare-host-key.sh: run on the admin workstation before an
install, generates the host's ed25519 keypair and prints the exact
steps to register its derived age key in nixos/.sops.yaml and
re-encrypt the affected secrets/*.yaml files.
- common.nix's auto-install.sh: after disko mounts /mnt and before
nixos-install, installs a pre-seeded key from /root/host-keys/ into
/mnt/etc/ssh/ if present, otherwise warns and asks for confirmation
before continuing without one.
- installer.nix now imports common.nix (previously only proxmox-lxc.nix
did), so the ISO/netboot path used for EFI VM installs gets the same
auto-install.sh and pre-seed check, not just the LXC path.
- Also fixes a pre-existing stray backtick in the disko invocation that
broke auto-install.sh's bash syntax entirely, independent of this
change (found while rendering the script to verify the new logic).
README.md documents the new pre-flight workflow.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>