A replica-set secondary falls behind the primary; the app will read stale data within a minute. Want an HTTP endpoint that says "ok" or "lag".
Monitoring cookbook
Hand-written recipes for the monitoring problems we see most often. Each recipe shows a minimal DIY script and the one-click Enterno.io monitor that covers the same concern without extra infrastructure.
Memcached fills up and starts evicting keys under load; the app cache-misses and hammers the DB. Want an evictions/min threshold.
Node app stalls under CPU-blocking operations; user latency creeps up. Want an endpoint that exposes the live event-loop-lag value.
Apache starts returning 502/503 from one backend but not all. Want an endpoint with the 5xx ratio over the last 60 s.
Site is on the HSTS preload list, but after an nginx refactor the header is gone. In 3 months the domain will be removed from the preload list. Need a daily check.
Real-time chat is up, but disconnects/sec are 3× the baseline — some intermediate nginx started dropping connections. Want an endpoint with the live rate.
A name-server misconfig leaks AXFR to the internet — every subdomain, MX, TXT (including SPF/DKIM keys) is visible to attackers. Daily check with alert.
Spring app is sluggish — long GC pauses (>500ms) every few minutes. Heap size was fine but the new-gen ratio is misconfigured. Want an endpoint with p99 pause.
Every week some analyst fires off a heavy SELECT without LIMIT and blocks other transactions. You want to know within a minute, not within an hour.
A release bumped the bundle size and p99 cold-start went from 800ms to 3s. The metric is in CloudWatch, but nobody’s watching. Want a heartbeat-style alert.
Sentinel performed a failover at 3 AM and nobody noticed. We want a notification the moment the master flips, not next week.
Caddy usually renews on its own, but once a Let's Encrypt rate-limit broke the cycle and we found out 2 days before expiry. Want a belt-and-braces daily check.
A CrashLoopBackOff in one namespace — kubectl shows a restart count of 47, but nobody sees it. Want an endpoint that returns high when the counter jumps.
A Worker auto-deploys from main. Once prod 5xx rate jumped to 12% — but dashboards get checked once a day. Want a per-minute probe.
An attacker is hammering a `limit_req_zone` — legit traffic now eats 429s too. The access log shows it but nobody is watching.
A `schedule:`-driven workflow sometimes silently stops (forked repos, expired tokens, GH outages). You only realise a week later when backups are missing.
You enabled `request_slowlog` in php-fpm.conf — but nobody reads it. Want an endpoint that returns high when > 5 slow requests show up in a minute.
Your `/stripe/webhook` endpoint started 500ing after a deploy — Stripe gave up after 5 retries. Payments lag a full 24h. We want a 60-sec alert.
API gateway deploys a new schema — the mobile team learns that a type was removed via the crash reporter. Want a snapshot every 5 min with a diff alert.
Under load the Tomcat connector pegs at `maxThreads=200` — new requests queue, p99 latency climbs. JMX has the metric but nobody is watching.
Have a recipe we missed?
Tell us which stack to cover next — drop a line to support@enterno.io and we'll add the recipe (and credit you on the page).
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