This check monitors the number of read, write and total locks
for the active clients and queued operations on a MongoDB instance.
You can configure levels for the read, write and total count.
Without configuration this check is always OK.
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, intead.
One service is created.