puppetlabs/puppetlabs-mongodb — pull request #128 by mkrakowitzer (2014-06-24 15:16:33+00:00)
Title: pidfilepath can not have spaces.

If the pidfile has spaces (pidfilepath = /var/run/mongodb/mongodb.pid) then you can not stop the service.
I am using version 2.6.3 from downloads-distro.mongodb.org

$sudo /etc/init.d/mongod stop
Stopping mongod: [FAILED]