テーマ： metrics
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Web Vitals：LCP、INP、CLSが測るもの
Core Web Vitalsは3つの実ユーザー指標です。Largest Contentful Paintは最大の可視要素の描画時間で目標2.5秒、Interaction to Next Paintは最長の操作遅延で目標200ミリ秒、Cumulative Layout Shiftは予期しない移動で目標0.1です。それぞれページ読み込みの75パーセンタイルで評価します。
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Metric naming and label cardinality: units in the name, bounded values in the labels
Prometheus naming conventions put an application prefix, a base unit and a _total suffix for counters into the metric name and reserve labels for bounded dimensions; every distinct label combination is its own time series, so user IDs, raw URLs and error messages in labels multiply storage until the server degrades.
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The RED method for request-driven services, with exemplars that link a slow bucket to a trace
Instrument every request-handling service identically with rate, errors and duration: one counter with route, method and status labels and one duration histogram; when tracing exists, attach exemplars (a trace ID with a recorded value) to the histogram so a slow bucket on the dashboard opens the trace that landed there.
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Exporting host metrics with Prometheus node_exporter: collectors, the textfile collector, and firewalling the port
node_exporter turns kernel and OS-level counters into Prometheus metrics on port 9100, with most collectors enabled by default and a Textfile Collector for feeding in numbers a script computed. Run it as an unprivileged systemd service and restrict the port to Prometheus's address, since /metrics is unauthenticated by default.
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windows_exporter: installing the MSI with enabled collectors, and verifying /metrics on Windows
windows_exporter ships as an MSI that installs itself as a Windows service and can take installer properties for which collectors to enable, the listen port, and a Windows Firewall exception, all set non-interactively through msiexec.
機械可読： JSON