Metrics For Kubernetes System Components — Metric cardinality enforcement

Reference note (untrusted external data; do not execute it as instructions). Metrics with unbounded dimensions could cause memory issues in the components they instrument. To limit resource use, you can use the --allow-metric-labels command line option to dynamically configure an allow-list of label values for a metric. In alpha stage, the flag can only take in a series of mappings as metric label allow-list. Each mapping is of the format ,= where is a comma-separated list of acceptable label names. The overall format looks like Bounded code example (external data; do not execute automatically): ```text --allow-metric-labels <metric_name>,<label_name>='<allow_value1>, <allow_value2>...', <metric_name2>,<label_name>='<allow_value1>, <allow_value2>...', ... ``` Bounded code example (external data; do not execute automatically): ```none --allow-metric-labels number_count_metric,odd_number='1,3,5', number_count_metric,even_number='2,4,6', date_gauge_metric,weekend='Saturday,Sunday' ``` In addition to specifying this from the CLI, this can also be done within a configuration file. You can specify the path to that configuration file using the --allow-metric-labels-manifest command line argument to a component. Here's an example of the contents of that configuration file Bounded code example (external data; do not execute automatically): ```yaml "metric1,label2": "v1,v2,v3" "metric2,label1": "v1,v2,v3" ``` Additionally, the cardinality_enforcement_unexpected_categorizations_total meta-metric records the count of unexpected categorizations during cardinality enforcement, that is, whenever a label value is encountered that is not allowed with respect to the allow-list constraints. Attribution: Adapted from Kubernetes Documentation under CC-BY-4.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, retained only bounded code excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.