Description of problem:
Mongodb recommends two preferred OS tunings for it to run optimally.  We probably want to implement these MonogoDB tunings on the controller machines that host Mongo as long as ceilometer is deployed and using Mongodb.

The tunings are printed in the Mongo console:

[root@overcloud-controller-0 lib]# mongo --host 172.21.33.20
MongoDB shell version: 2.6.9
connecting to: 172.21.33.20:27017/test
Welcome to the MongoDB shell.
For interactive help, type "help".
For more comprehensive documentation, see
	http://docs.mongodb.org/
Questions? Try the support group
	http://groups.google.com/group/mongodb-user
Server has startup warnings:
2015-10-15T17:52:08.004-0400 [initandlisten]
2015-10-15T17:52:08.004-0400 [initandlisten] ** WARNING: You are running on a NUMA machine.
2015-10-15T17:52:08.004-0400 [initandlisten] **          We suggest launching mongod like this to avoid performance problems:
2015-10-15T17:52:08.004-0400 [initandlisten] **              numactl --interleave=all mongod [other options]
2015-10-15T17:52:08.004-0400 [initandlisten]
2015-10-15T17:52:08.004-0400 [initandlisten]
2015-10-15T17:52:08.004-0400 [initandlisten] ** WARNING: Readahead for /var/lib/mongodb is set to 4096KB
2015-10-15T17:52:08.004-0400 [initandlisten] **          We suggest setting it to 256KB (512 sectors) or less
2015-10-15T17:52:08.004-0400 [initandlisten] **          http://dochub.mongodb.org/core/readahead
tripleo:PRIMARY>