6dc77f4612
Documents the 2026-06-13 right-sizing review: Kuma is already lean (~1 check/s, 227 monitors mostly at 300s, 77MB on shared MySQL, 30d retention); the 'scraping too much' concern traced to a fixed socket.io login-timeout incident, not load. Records the deliberate decisions (keep per-service [External] monitors over canaries; keep datastore on shared mysql.dbaas) with rejected alternatives + rationale, plus the known internal-sync no-prune gap (stale Goldilocks monitor cleaned up by hand). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Uptime Kuma — Context
Glossary for the uptime-kuma monitoring context. Terms only — no implementation
detail. Decisions live in docs/adr/.
Glossary
Active check (poll) — Uptime Kuma actively probes a target on an interval (HTTP / TCP / ping / DB). This is polling, not "scraping." Prometheus scrapes exporters; Kuma polls targets. (Note: Prometheus does not scrape Kuma — a separate monitoring lane.)
Monitor — one configured target plus its check definition.
Internal monitor — probes a service on its in-cluster address
(*.svc.cluster.local). Answers "is the service itself healthy?"
[External] monitor — probes a service via its full public path
(DNS → Cloudflare → cloudflared tunnel → Traefik). Answers "is the service
reachable the way users reach it?" Maintained one-per-externally-reachable-service
by deliberate choice (see ADR-0001).
Heartbeat — one recorded check result (up/down + latency), persisted to the datastore.
External-access divergence — the condition where a service is healthy
internally but its [External] path is down — i.e. the shared
Cloudflare/tunnel/Traefik path is broken while the service itself is fine.
Surfaced by the ExternalAccessDivergence alert.