Which of the following does NOT involve custom namespace monitoring?

The option stating that monitoring all nodes in a cluster does not involve custom namespace monitoring is accurate because custom namespace monitoring specifically targets certain namespaces within a cluster. In contrast, monitoring all nodes includes capturing data across the entire cluster without any specialization or filtering based on specific performance requirements.

Custom namespace monitoring is often used to zoom in on particular workloads or services, allowing for tailored performance insights and optimization efforts. The other scenarios listed—focusing on selected namespaces, reporting performance data exclusively for certain workloads, and reducing overhead for specific environments—are activities that directly engage with customizing which namespaces are monitored based on specific goals or requirements. Therefore, the general approach of monitoring all nodes, which encompasses everything, does not align with the principles of custom namespace monitoring.