ducoterra
e94d4f718c
Ties the two runbooks together as one host-agnostic directory: which runbook solves which problem, a file -> target-path map for the units, and the shared deploy pattern (one tar | ssh pipe into /root, then install with explicit modes rather than copying a whole tree into /etc). States the conventions both units follow - configs under /usr/local as the source of truth with thin systemd wrappers, idempotent installers that re-derive desired state and never delete what they did not create, and gap-limited self-healing so a broken dependency cannot make a unit flap. Also documents the redaction recipe for pasting a WireGuard config: match `PrivateKey[[:space:]]*=` because wg-quick strip emits spaces around the `=`, which a `PrivateKey=` regex misses. LLM-Generated: true
Raspberry Pi — boot-time hardening units
Two reusable runbooks for a headless Pi that must stay reachable over SSH.
Deliberately host-agnostic: no addresses, key material, or peer identities
live in this repo — those stay on each host. Set HOST and fill in the
placeholders from the runbook before running anything.
| Runbook | Solves |
|---|---|
root-ssh-key.md |
root authorized_keys gets wiped (imaging, config management) → key is re-installed at boot and re-applied on change |
wireguard.md |
SSH through a WireGuard tunnel address fails after reboot / NAT timeout / roaming to another network |
Verified against Debian 13 (trixie) with systemd 257 and NetworkManager. The
units are plain POSIX sh + systemd, so they carry to any other distribution
with the same systemd version or newer.
Layout → target path on the host
| File in this directory | Installs to |
|---|---|
ensure-root-ssh-key |
/usr/local/sbin/ensure-root-ssh-key (0755) |
ensure-root-ssh-key.service |
/etc/systemd/system/ |
ensure-root-ssh-key.path |
/etc/systemd/system/ |
root-ssh-keys/authorized_keys.example |
/usr/local/share/root-ssh-keys/authorized_keys (0644) — copy, fill in your public key(s) |
wg0-watchdog |
/usr/local/sbin/wg0-watchdog (0755) |
wg0-watchdog.service |
/etc/systemd/system/ |
wg0-watchdog.timer |
/etc/systemd/system/ |
wg-quick@wg0.service.d-10-boot-resilience.conf |
/etc/systemd/system/wg-quick@wg0.service.d/10-boot-resilience.conf |
wg0.conf.template |
documents /etc/wireguard/wg0.conf (0600) — the real file is never copied here |
Deploy pattern
Every command in both runbooks follows the same shape, so a fresh Pi needs only
HOST and the placeholders:
HOST=root@<pi-address>
D=$PWD # run the snippets from a checkout of this directory
Files travel over one tar | ssh pipe into /root, then install moves them
into place with explicit modes (no scp of a whole tree into /etc, no
ambiguous ownership). Reload and enable once at the end:
ssh "$HOST" 'systemctl daemon-reload && systemctl enable --now <units>'
Conventions worth keeping on any host
- Config files under
/usr/local/{sbin,share}are the source of truth; systemd units stay thin wrappers so they can be re-imaged independently. - Idempotent installers over clever state: every script re-derives the desired state from its own config file and never deletes what it did not create.
- Anything that must heal itself is gap-limited (a minimum interval between restarts) so a broken dependency cannot make a unit flap.
- Private keys and addresses are excluded from the repo; when dumping a
WireGuard config, redact with a regex that tolerates
PrivateKey =spacing (wg-quick stripemits spaces, aPrivateKey=regex misses them):sed -E 's/^(PrivateKey[[:space:]]*=).*/\1 [REDACTED]/'