MENU
Given the following Histogram metric data, how many requests took less than or equal to 0.1 seconds?
apiserver_request_duration_seconds_bucket{job="kube-apiserver", le="+Inf"} 3
apiserver_request_duration_seconds_bucket{job="kube-apiserver", le="0.05"} 0
apiserver_request_duration_seconds_bucket{job="kube-apiserver", le="0.1"} 1
apiserver_request_duration_seconds_bucket{job="kube-apiserver", le="1"} 3
apiserver_request_duration_seconds_count{job="kube-apiserver"} 3
apiserver_request_duration_seconds_sum{job="kube-apiserver"} 0.554003785
In Prometheus, histogram metrics use cumulative buckets to record the count of observations that fall within specific duration thresholds. Each bucket has a label le (''less than or equal to''), representing the upper bound of that bucket.
In the given metric, the bucket labeled le='0.1' has a value of 1, meaning exactly one request took less than or equal to 0.1 seconds. Buckets are cumulative, so:
le='0.05' 0 requests 0.05 seconds
le='0.1' 1 request 0.1 seconds
le='1' 3 requests 1 second
le='+Inf' all 3 requests total
The _sum and _count values represent total duration and request count respectively, but the number of requests below a given threshold is read directly from the bucket's le value.
Verified from Prometheus documentation -- Understanding Histograms and Summaries, Bucket Semantics, and Histogram Query Examples sections.