Zenoss • Zenoss is an open source platform released under the GNU General Public License (GPL) version 2. • It provides an easy-to-use Web UI to monitor performance, events, configuration, and inventory. • Zenoss is one of the best for unified 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).