The Geek Stuff posted a guide about installing Zenoss Core for Monitoring on Linux CentOS / RHEL

Zenoss is an open source agentless monitoring tool.

The main advantage of zenoss is that you don’t need to install any software on the client side for monitoring.

Zenoss has the following two versions:

Zenoss Core (this is free)
Zenoss Enterprise. This is also called as Zenoss Resource Manager, which is a paid version. This provides several additional features: High-availability, distributed architecture, event correlation, etc.

  How to Install Zenoss Core for Monitoring on Linux CentOS / RHEL