FOSS Linux published a guide about installing and configuring Graylog on CentOS 7.
How to install & configure Graylog on CentOS 7
Graylog is an open-source log management system. This tutorial provides a step-by-step guide on installing and configuring Graylog with SSL on CentOS 7.
How to install & configure Graylog on CentOS 7 | FOSS Linux