graylog 관련

https://packages.graylog2.org/el/stable

- graylog2 install in CentOS 7

http://www.itzgeek.com/how-tos/linux/centos-how-tos/how-to-install-graylog2-on-centos-7-rhel-7.html

- graylog2 install in CentOS 6

http://www.richardyau.com/?p=377

- High Availability Log Processing with Graylog, MongoDB and ElasticSearch

http://severalnines.com/blog/high-availability-log-processing-graylog-mongodb-and-elasticsearch