Zenoss

Zenoss is an open source platform released under the GNU General Public License (GPL) version 2. It provides an easy monitoring since it is cloud agnostic and is open source. Zenoss provides powerful plug-ins named Zenpacks, which support monitoring on hypervisors (ESX, KVM, Xen and HyperV), private cloud platforms (CloudStack, OpenStack and vCloud/vSphere), and public cloud (AWS).