alerting

The exporter offers hundreds of fields and about a dozen of them change decisions. The health fields that predict failure, the performance fields that tell you whether work is happening, the one everybody alerts on that means nothing, and the diagnostic levels with the time each takes.

A training run has one number that matters and a handful that explain it. Goodput as the top-level metric, the per-rank timing that finds a straggler among a thousand, the hardware layer beneath it, and the three dashboards that serve three different people asking three different questions.

Four objectives, each measured at a percentile because averages hide the experience you are promising. The error budget in minutes per month, the burn-rate arithmetic that catches a fast failure in an hour and a slow one in a day, and why two of the four need separate targets per traffic class.

Four mechanics do most of the work: symptom-based rules rather than cause-based, burn rate rather than thresholds, deduplication so one event is one page, and suppression during known windows. The arithmetic for each, and the rule that keeps the set from growing forever.