GetMetricUsageRatio takes in a set of metrics and a target usage value, and calculates the ratio of desired to actual usage (returning that and the actual usage).

GetResourceUtilizationRatio takes in a set of metrics, a set of matching requests, and a target utilization percentage, and calculates the ratio of desired to actual utilization (returning that, the actual utilization, and the raw average value).

PodMetric contains pod metric value (the metric values are expected to be the metric as a milli-value).

MetricsClient knows how to query a remote interface to retrieve container-level resource metrics as well as pod-level arbitrary metrics.

PodMetricsInfo contains pod metrics as a map from pod names to PodMetricsInfo.