MongoDB: Replica Info
This check shows the primary, secondary and arbiter hosts from a MongoDB cluster.
If the replica set does not have a primary node, the check will report a warning.
Note: If the MongoDB is running as a replica set, this check is not discovered
on the same host where the
mk_mongodb plugin is installed. The data is piggybacked
to a pseudo host named after the replica set name instead.
One service is created.