This document discusses monitoring tools for cloud environments and introduces Zenoss as a holistic monitoring solution. It highlights Zenoss' powerful plugins called ZenPacks that provide APIs and monitoring capabilities for various cloud platforms including CloudStack, OpenStack, hypervisors like ESX, KVM and Xen, and cloud services from AWS. Examples of metrics monitored for CloudStack and OpenStack with ZenPacks include network usage, memory usage, object load averages and images/flavors. Resources for getting started with Zenoss are also provided.