The customer is running OpenShift 4.6.19 and currently working on migrating from custom monitoring Prometheus operator setup to openshift-user-workload-monitoring.

Requirement:- One of the requirements we have is to maintain support for having serviceMonitors defined in one namespace scraping services defined in a different namespace.

As per- https://github.com/openshift/enhancements/blob/master/enhancements/monitoring/user-workload-monitoring.md

This functionality is disabled on purpose for "openshift-user-workload-monitoring" with ignoreNamespaceSelectors=true as described in above link and statement from the above link as below.

"PodMonitors and ServiceMonitors objects have a field to select which namespaces the Endpoints are discovered from, these could be a potential DDOS risk as a user could specify any namespace even the ones they do not have access to. To avoid this risk we will introduce a ignoreNamespaceSelectors in the Prometheus Custom Resource, and set that to true in cluster-monitoring-operator. This will discard the namespaceSelector field users specify and avoid the above mentioned risks."

The customer wants to change ignoreNamespaceSelectors to "false" that they achieve the requirement or an alternative way to do the same.