personal_infra/ansible/host_vars/monitoring/main.yml

---

# Systemd services deployed on this host, monitored every 5 minutes.
#
# The fact lives with the machine rather than in a central map, for the same
# reason the cross-host ports do: "what runs here" is a property of the host,
# and a central list is one more thing to forget to update when a service moves.
#
# Only units WE deploy belong here. Distro units (ssh, cron) have their own
# supervision and would be noise.
monitored_services:
  - caddy
monitoring: systemd services, domain expiry, DNS correctness, public endpoints Four more check types, 42 endpoints, taking the estate from 39 to 81. ── systemd services (infra/401) ──────────────────────────────────────────── Every unit we deploy, checked every 5 minutes with a 16-minute heartbeat. This closes the gap that let a real bug run unnoticed earlier today: a backup script left forgejo, lnbits, headscale and memos stopped, and NOTHING caught it. The dumps exited 0, the artefacts were correct, the deploy said failed=0, and liveness only proves the HOST is up - not that anything on it serves. One endpoint PER UNIT but only ONE timer per host: the check iterates that host's units and pushes a result for each, the way check-backups.sh reports per source. Four units on vipy would otherwise mean four scripts, services and timers. A single host-level red light would also say "something on vipy is down" without saying which, which is not the question anyone has. Keys are host-qualified because unit names collide - caddy runs on four machines. Which units a host runs lives in host_vars/<host>/monitored_services, because "what runs here" is a property of the machine, the same reasoning as the cross-host ports. nut-driver-enumerator is deliberately excluded: it is a oneshot generator that is `enabled` but always `inactive`, so it would report down forever. Checked live before excluding it. ── domain, DNS and public endpoints (infra/402) ──────────────────────────── The first checks that PULL rather than push, and that is the right way round: all three are about how the outside world sees us, so they must be measured from outside. Nothing is installed anywhere - no script, no timer, no token. They also have no heartbeat, because a heartbeat answers "did the reporter report"; when Gatus does the checking itself, failure is immediate. domain 1 endpoint, 24h, [DOMAIN_EXPIRATION] > 336h (two weeks) dns 11 endpoints, 24h, [DNS_RCODE] == NOERROR and [BODY] == the IP public 14 endpoints, 5m, 11 HTTPS + 3 TCP Expected A records are derived from inventory (hostvars[host].ansible_host), not written down again. The estate's recurring bug is an address recorded in a second place and left behind when the machine moved; asserting against inventory means a renumbered box is one edit, not two. Expected HTTP status was checked live per site rather than assumed. Two return 401 - the Gatus dashboard and the DATUM dashboard, both behind basic auth - and that is what is asserted: expecting 200 there would go green precisely when the auth broke. headscale asserts /health rather than /, which is a 404 by design. Every HTTPS check also carries [CERTIFICATE_EXPIRATION] > 168h, which is free on an endpoint already being polled and catches a renewal that silently stops. Two things learned the hard way, both now in comments: * A domain-expiry endpoint needs a URL SCHEME. Gatus derives the endpoint type from the prefix (endpoint.Type()), so a bare "contrapeso.xyz" is UNKNOWN and the whole config is rejected. It is https:// plus a DOMAIN_EXPIRATION condition and no status assertion, so the registrar's parking page at the apex is irrelevant. Upstream also enforces a 5m minimum interval for that placeholder, because it uses a free whois service. * That rejection proved skip-invalid-config-update was worth adding. Gatus logged "the configuration file was updated, but it is not valid, the old configuration will continue being used" and kept running. Without it the reload path calls panic() and one malformed contributed file takes the monitor down. Verified: 15/15 service endpoints UP; 26/27 public-facing UP. The single DOWN is public_memos, correctly - memos-box is powered off, and the condition result reads [STATUS] (502) == 200. memos-box and arbret-staging-box were shut down deliberately from the Proxmox UI to test the liveness endpoints; their endpoints stay registered and will go green when the VMs return. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> 2026-09-14 09:33:57 +02:00			`---`

			`# Systemd services deployed on this host, monitored every 5 minutes.`
			`#`
			`# The fact lives with the machine rather than in a central map, for the same`
			`# reason the cross-host ports do: "what runs here" is a property of the host,`
			`# and a central list is one more thing to forget to update when a service moves.`
			`#`
			`# Only units WE deploy belong here. Distro units (ssh, cron) have their own`
			`# supervision and would be noise.`
			`monitored_services:`
			`- caddy`