The question asks for the number of requests that took less than or equal to 0.1 seconds. In Prometheus, a Histogram metric type uses cumulative buckets to track observations. The time series apiserverrequestdurationsecondsbucket with the label le="" represents the count of observations that are less than or equal to that upper bound.

The line apiserverrequestdurationsecondsbucket{job="kube-apiserver", le="0.1"} 1 explicitly states that the cumulative count of requests with a duration less than or equal to 0.1 seconds is 1.

A. This is the value for the le="0.05" bucket, which counts requests taking 0.05 seconds or less, not 0.1 seconds.

B. This is the value of the sum metric, representing the total cumulative duration of all requests, not the count of requests.

D. This is the value of the count metric, which represents the total number of all requests observed, regardless of their duration.

1. Prometheus Documentation, Metric Types, Histogram: The official documentation explains that a histogram exposes cumulative counters for observation buckets as bucket{le=""}. This confirms that the value associated with le="0.1" is the count of observations less than or equal to 0.1. (Source: Prometheus.io, Metric types | Histogram, Section: "Histogram").

2. Kubernetes Documentation, System Metrics: The Kubernetes documentation lists apiserverrequestdurationseconds as a key API server metric. It is described as a "Histogram of request latency in seconds, broken down by verb, group, version, resource, and scope." This confirms the metric's purpose and type. (Source: Kubernetes.io, Metrics For Kubernetes System Components, Section: "API server metrics").