Real walkthroughs for watching the things you can't afford to have fail.
One cron line on a GL.iNet or OpenWrt router sends a heartbeat; the silence becomes your alert — delivered over cellular, so “my internet is down” can actually reach you. Plus outage receipts for your next ISP support call.
A webhook turns a #alerts channel into a pager: free push to your phone, scrollable history, everyone sees the same outage. Exact menu paths, the notification setting everyone misses, and the escalation ladder for when Discord isn’t enough.
192.168.x.x, localhost and anything behind a firewall cannot be reached by an external checker — by any service, at any price. Turn the connection around instead: an agent that reports out, or a heartbeat the machine sends in. Neither needs an open port.
Everyone starts by alerting on CPU, which is the metric least worth paging on — it produces false positives and false negatives. A ranking of what to page on, what to only chart, and the two settings that matter more than any threshold.
Self-hosted monitoring is excellent at everything except the outage that takes the host down with it — power, panic, network, terminated instance. Why that gap never shows up in testing, and the smallest thing that closes it.
A node went quiet for 109 seconds and came back on the wrong kernel. The journal was empty, last printed nothing, and wtmpdb boottime said the boot time could not be found. Where the answer actually was.
Your Proxmox host can sit at 4% CPU while a VM has been off since Tuesday. Watch guests, storage and quorum with one config section — then build a ladder that pings Discord first and texts you if nobody looks.
A few tracebacks an hour is life on the internet; forty in five minutes is an incident. How to page on an error-rate spike and get the actual traceback delivered in the alert — no Sentry SDK, no log pipeline, one config line.
Two Raspberry Pis at home and a cloud web server — watched end to end, with alerts to Discord, without paying a cent. A real walkthrough with every click.
"Up" is four separate facts: DNS, network, app, content. Layer dns + ping + http/s monitors (and a beacon if you host) so the alert tells you what broke, not just that something did.
Cron runs your backups and jobs in silence — and stays silent when they break. Five real ways to get a page when a job fails or, worse, never runs at all. Bash you can copy, tradeoffs spelled out.
Your UniFi console goes quiet the moment you close the tab. Turn a switch, gateway or AP into a monitored device with real alerts — SNMP polled from inside your network, nothing exposed to the internet.
CPU, memory, and disk on a handful of boxes — with a page when one breaks — and none of the Prometheus overhead. Push-based, works behind NAT, no open ports, with a real 6 AM incident to show it working.
Backups don't fail loudly — they stop quietly, and you find out during the restore. Real restic and borg examples, a dead-man's-switch heartbeat, and the honest bit about verifying restores.
Give your team an on-call agent that acks the alert, reads your runbook, investigates on your own boxes, and writes back evidence — before a human is ever woken. Works with any MCP agent; we use Claude. A full walkthrough for IT teams.