The PrometheusRule custom resource definition (CRD) defines [alerting](https://prometheus.io/docs/prometheus/latest/configuration/alerting_rules/) and [recording](https://prometheus.io/docs/prometheus/latest/configuration/recording_rules/) rules to be evaluated by Prometheus or ThanosRuler objects.
Prometheus and ThanosRuler objects select PrometheusRule objects using label and namespace selectors.