Users Guide

Introduction to the VMware Virtual Infrastructure 27
VMware Virtual Infrastructure Overview
Virtual Objects
Virtual objects can exist only within the confines of the virtual infrastructure. With the
exception of virtual machines, virtual objects are logical and are used for organizing
VMware ESX Servers and virtual machines, either geographically or by function. In
addition, virtual objects allow for the advanced configuration of resource management
and of high availability settings.
Virtual Machines
The creation and subsequent use of virtual machines is the primary purpose for building
and maintaining a virtual infrastructure. Virtual machines share many of the
characteristics of physical systems (like storage and network interaction), but they do
not have direct access to the hardware that is used to process their information and they
are considered virtual components within the virtual infrastructure.
A virtual machine encompasses more than just a guest operating system like Microsoft
Windows. A virtual machine also contains specific configurations that help to define it,
such as the number of processors and the amount of memory it can leverage.
All of the resource utilization for a particular virtual machine on a VMware ESX Server
is scheduled through that Server's hypervisor. The efficient tracking and analysis of this
scheduling of resources at both the virtual machine and the ESX Server Host level is a
key function provided by the vFoglight Cartridge for VMware.
At any given time a virtual machine must reside on a single VMware ESX Server, but it
can be moved across physical ESX Servers, typically without downtime, through the
use of key VirtualCenter functionality called VMotion. VMotion provides a method for
proactively moving a virtual machine from one ESX Server to another while avoiding
the downtime that can arise from having to perform actions like patching a physical host
server. VMotion also provides a manual method a system administrator can use to better
balance virtual machine workloads based on resource utilization trends.
A VMware Cartridge feature called Migration Modeler provides a method for analyzing
the impact of using VMotion to move a virtual machine between two VMware ESX
Servers in a Cluster. Migration Modeler provides this functionality without you actually
having to move the virtual machine.
vFoglight Cartridge for VMware also provides a mechanism that tracks the lifecycle of
the virtual machines within the virtual infrastructure. This enables you to quickly and
easily view a history of a virtual machine's performance metrics and a history of its
logical location within the virtual infrastructure.