Metrics

• A metric is a time series - a stream of (timestamp, value) numbers

# name: http_requests_total
# labels: {method="GET", status="200", service="checkout"}
http_requests_total{method="GET", status="200", service="checkout"}
→  [ (t1, 5), (t2, 9), (t3, 14), ... ]

• Every unique combination of name + labels are different time series

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• Prometheus collects and stores its metrics as time series data, i.e. metrics information is stored with the timestamp at which it was recorded, alongside optional key-value pairs called labels

Attributes

• Each metric has type and help attributes
• Help: description of what the metrics is
• Type: there are three types
  • Counter: How many times happened
  • Gauge: The current value now
  • Histogram: how long or how big

Examples

ALERTS{alertname=~"service_is_down.*", service=~".*"}

• Percentiles: p90, p95, p99
• Trimmed mean: tm90, tm95, tm99