Using Prometheus to monitor Caché ，when config application /metrics done， Prometheus connection error: “server returned HTTP status 404 Not Found”

Before SAM, there was no way to monitor Cache or IRIS using Prometheus out of the box. You had to implement the metrics exporter API yourself or use a community implementation like the one you linked. Since 2020.1, the /api/monitor API is provided by InterSystems out of the box. SAM uses this API to collect metrics and alerts from servers.