Tech analysis: With the increasing popularity of virtualization comes a new problem: virtual sprawl. Keep your virtual machines under control with patch management and inventory software.
More and more IT
organizations are embracing virtual server and desktop infrastructure
technologies. A December 2009 report from Forrester Research found that 71
percent of the companies it surveyed are using server virtualization and
believe that 62 percent of their x86 server OS instances will be virtualized
with the next two years. Virtual desktop implementations lag behind, but are
gaining ground. A December 2009 study by Ziff Davis Enterprise's own Baseline
found that 30 percent of participating executives expected deployment of VDI to
increase at their companies.
For all the benefits that
virtualization can deliver, the technology does not erase the need for
physical-world management tasks such as prompt patching and, where appropriate,
antivirus protection. In fact, some of virtualization's standout virtues-agility
and flexibility, for instance-can double as management vices, particularly when
it comes to managing these easily minted virtual machines as they move through
their life cycles.
Rapid growth of virtual
machines (both their images and their instances) can lead to a condition known
as "virtual sprawl," in which lapses in basic care and feeding of
multiplying, unaccounted-for virtual instances can present major IT and
organizational challenges to enterprises.
Dealing effectively with VM
lifecycle management boils down in large part to focusing on the management practices
that worked in the physical world, beginning with well-planned golden images,
adherence to timely patching regimes and careful system inventory. Certainly,
these practices work a bit differently in the virtual world, so the key to
success is watching out for virtual pitfalls and maximizing the advantages
inherent in virtual platforms.
What's behind virtual sprawl?
implementations are focused on solving problems that were challenging when
managing a one-to-one relationship between physical machines and software (OS
and applications) such as underutilization and difficulties in providing
management and security.
enterprises suffered from what amounted to "physical server sprawl"-the
result of years of building underutilized, heterogeneous, power-hungry and
unmanageable server farms in fits and spurts as budget was available. This
doesn't even take into account the difficulties involved in managing tens of
thousands of physical desktops, pushing OS and application patches, enforcing
security policy, and accepting that users typically need enough privileges to
screw things up.
At first glance
virtualization seems a natural solution to the problems of physical computing. Virtual
machine images are more convenient to work with than physical machines because
they can be treated, in essence, as data.
But now enterprises are
starting to see a different kind of sprawl-virtual machine image sprawl. Virtual
machine images are cloned, versioned, archived and, when in use, changed over
time. The cost of physical server hardware controlled physical server sprawl
somewhat, but virtual machines can be created, manipulated, duplicated and
reconfigured without costing anything more than disk space. With the cost
barrier removed, IT organizations are free to create countless virtual machine
images with myriad configurations. Consider this the entry point for virtual
sprawl, which, if not combated quickly and decisively, can ran rampant
throughout an IT organization.
How does the sprawl grow?
Each physical server is replaced by a virtual server image. Virtual server
images are typically stored in a massive SAN (storage area network) environment,
reaching hundreds of terabytes and even petabytes in some organizations, and
deployed to a smaller number of well-utilized, homogeneous, commodity physical
servers. Client machines (meaning an OS, apps, configuration and perhaps data)
can be replaced by virtual desktops containing the same. But once deployed, no
two virtual clients can truly remain the same for very long. Snapshots, clones,
changes that are made and then rolled back, or not-all of this adds up to an
explosion in the number of virtual machine images that must be catalogued,
maintained, deployed and managed within an organization.