The documentation is currently lacking examples of user-defined roles: http://docs.mongodb.org/master/core/authorization/#user-defined-roles

A tutorial with examples for a few common scenarios would be helpful.

Possible examples:

• mms agents: http://mms.mongodb.com/help/management/permissions/
• mongodump: http://docs.mongodb.org/manual/reference/program/mongodump/#required-user-privileges
• mongostat: http://docs.mongodb.org/manual/reference/program/mongostat/#cmdoption-mongostat--username
• currentop/killop: SERVER-12593