This blog post outlines an efficient method for managing Prometheus metrics at scale, particularly for users dealing with a large number of individual rule groups. The solution involves leveraging PromQL joins to aggregate metrics more effectively by appending labels from one metric to another at query time, thus eliminating the need for numerous individual rules. The post explains how info metrics can be used to encode high cardinality label values, which can then be joined with other metrics. It highlights the utility of the textfile collector in the Prometheus Node Exporter and Grafana Agent to quickly generate static metrics that are useful for PromQL queries. By repurposing existing tooling to generate a Prometheus metrics file and using a single rule per metric to inject the appropriate reference label, users can achieve the same results as their previous setup but with significantly fewer rules, enhancing both efficiency and manageability.