Information reported by Atlas UI to monitor sharded clusters is retried invoking a set of commands exposed by MongoS and MongoD (see SERVER-79185).

By embedding the router service into MongoD, these commands should be exposed from the main and router ports maintaining the same behavior as compared to having two separate processes.

The serverStatus command, for example, retrieves metrics from the ServerStatusSectionRegistry (SERVER-79353) and the MetricTree (SERVER-79352), but others count events by using custom variables.

The goal of this ticket is to identify these commands implemented using the custom variable and evaluate a solution to keep separate statistics for router and service.