In Prometheus, which metric type represents a value that can arbitrarily go up or down, like temperature or memory usage?

In Prometheus, which metric type represents a value that can arbitrarily go up or down, like temperature or memory usage?

• A. Counter
• B. Gauge
• C. Summary
• D. Histogram

Answer: (B)

Gauges are for values that can rise and fall over time. In Prometheus, a Gauge represents a single numeric value that can arbitrarily go up or down, so it fits metrics like temperature or memory usage where the current state matters and can fluctuate. This is different from a Counter, which only increases (and may reset on restart) to track cumulative events. Summaries and Histograms, on the other hand, collect distributions of observed values (like latency or request sizes) and are used to understand overall behavior over a period, not the instantaneous value. So the value that can change up or down at any moment is best represented by a Gauge.

Gauges are for values that can rise and fall over time. In Prometheus, a Gauge represents a single numeric value that can arbitrarily go up or down, so it fits metrics like temperature or memory usage where the current state matters and can fluctuate. This is different from a Counter, which only increases (and may reset on restart) to track cumulative events. Summaries and Histograms, on the other hand, collect distributions of observed values (like latency or request sizes) and are used to understand overall behavior over a period, not the instantaneous value. So the value that can change up or down at any moment is best represented by a Gauge.