This document provides an overview of virtualization technology. It discusses how virtualization works through the use of a hypervisor and management software to allocate resources across virtual machines. The benefits of virtualization include server consolidation and increased efficiency. Issues that need to be addressed include performance considerations when consolidating workloads, security risks introduced by added software layers, and ensuring compliance across virtual machines. The document provides guidance on getting started with virtualization, including understanding workloads, building a business case, training staff, and examining policies.

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P O W E R E D B Y :
Virtualisation
A Practical Guide for Solution Providers

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Virtualisation
A Practical Guide for
Solution Providers
Since the early days of computing, there has been a push to utilise compute resources
as efficiently as possible. In the 1960s, IBM developed Virtualisation technology as a
way to break a single physical mainframe computer into several logical partitions. Each
partition could host a separate application, allowing the mainframe to multitask. To enable
this partitioning, IBM designed the mainframe with Virtualisation in mind, optimising
the hardware to run a Virtual Machine Monitor (VMM) that controlled the partitions
(also known as virtual machines). This VMM was originally termed a supervisor, but as it
extended to control multiple machines, it became known as a hypervisor.
In the 1980s and 1990s, the client-server model
along with lower prices for hardware with greater
capabilities caused Virtualisation to became a lower
priority. Customers could buy multiple inexpensive x86
machines to replace mainframes, and x86 hardware
and the Windows operating system were optimised
to run single applications. Eventually, cost pressures
drove new demand to virtualise x86 systems as
well. Virtualisation gained a new life when VMWare
introduced a hypervisor that could run on x86
architecture.
Virtualisation has become a critical component of
many corporate IT strategies and is a foundational
technology in cloud computing. However, CompTIA
research finds that although firms are moving rapidly
into the cloud, there is less adoption and familiarity
with Virtualisation. Understanding this underlying
element of the cloud will help these firms better
understand how to address issues such as cost
structure and security.
How Virtualisation Works
The primary function of Virtualisation is to allocate
resources intelligently for optimal use. This is done
mainly through two pieces of hardware: the hypervisor
and the management software. In a single-application
environment, the operating system is installed directly on
the hardware, and subsequent applications are installed
in the operating system. Operating systems derive their
Source: IDC 2010 Server Virtualisation Module
2011 2012 2013 2014
200 2012 2012 2013
Growing Virtualisation Needs
Physical Server Shipments
(in millions)
Virtual Machines
(as a share of total server market)
7.7
19%
20%
22%
23%
8.2
8.6
9
As physical machine ship-
ments are growing, virtual
machines are growing even
more rapidly and becoming
a larger part of the overall
server market.

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power from the fact that they have intricate knowledge of the
hardware, using a kernel that directly communicates with the
processor, memory, and other devices. The hypervisor performs
the same function, but instead of applications being installed
on the hypervisor, complete operating systems are installed. A
hypervisor directly accesses the hardware of the host system,
and then presents subsets of those resources to each operating
system that is installed, creating virtual machines that are
completely self-contained.
While the hypervisor is the enabler of Virtualisation,
the management software is the differentiator among
Virtualisation vendors. As Virtualisation implementations
become more and more complex, the need to manage
becomes more critical. Management software provides
the ability to monitor virtual machines and ensure they are
operating properly. It also allows system administrators to
optimise the resources that are being allocated among all
virtual machines.
Server Virtualisation is the most common application of the
technology, but storage and networks have also become
candidates for Virtualisation. Network-Attached Storage (NAS)
and Storage Area Networks (SANs) provide abstracted storage
options for virtual machines to access. SANs are more expensive
implementations and are typically used by large enterprises.
Virtual Local Area Networks (VLANs) can group devices on a
network logically rather than physically, giving administrators
the ability to resegment networks without physically rearranging
devices or connections. These advances are leading to the
notion of a fully virtualised data centre, and as all three
Virtualisation techniques are employed, the management
software becomes increasingly important.
Benefits of Virtualisation
Most Virtualisation projects begin as an effort to consolidate
resources, gaining back efficiencies that were lost as servers
were underutilised by the applications running on them. As
resources are consolidated, the number of physical servers or
storage devices needed to maintain operations decreases. This
in turn reduces the energy demands of the resource pool.
There are some benefits to be realised in managing the
physical infrastructure in a virtual environment. New machine
requests no longer require approval of a complete system
and integration into a data centre. Instead, a machine that
is acting as a host may simply need additional memory to
accommodate new requests.
In addition to the data centre changes, the structure of an IT
department will change. Management of a virtual environment is
less labour-intensive, though the work itself is of a different nature.
Installation and maintenance are much simpler and happen much
faster in a virtual environment, and applications can more easily be
moved between virtual machines. Those personnel who previously
supported physical servers can be allocated to other IT work that
advances the objectives of an organisation.
• Nationwide Insurance reduced its number of physical
servers from 5000 to 3500 and increased utilisation rates
from 10% to 65%. This reduced hardware and operating
system support costs 20%-50%.
• St. Vincent’s Hospital Manhattan was able to achieve a
50% reduction in servers. In addition, the hospital found
that Virtualisation could be used to establish development,
test, and production environments without the cost of
three separate infrastructures.
• The Berryessa Union School District in California
consolidated 32 conventional servers to four blade servers.
Desktop resources doubled from 700 to 1400 available
systems, and fix time improved from weeks to minutes as
onsite visits were replaced by virtual machine repair.
Examples of Virtualisation Savings
Note: the diagram shows a form of server Virtualisation known as bare-metal
Virtualisation. Diagrams showing hosted Virtualisation and OS Virtualisation
can be found in the appendix.
Virtual Machine Virtual Machine
App App
OS OS
Hypervisor
Hardware
App
Hardware
App App
OS
App
App App App
Virtual Machine
OS
App App App
Non-virtualised server
Virtualised server

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The changes in the IT department do not end with virtual
machine management, though. Virtualisation opens the
door for more robust features and increased flexibility.
Backup and disaster recovery are implemented differently,
but more simply, than in a physical environment.
The ability to quickly move applications or bring up
new machines brings a new level of agility. Adding in
intelligence for resource utilisation and dynamic allocation
of those resources is what can then turn Virtualisation into
a cloud solution.
As organisations move more of their operations into the
cloud and also grapple with the implications of mobile
device use within the corporation, Virtualisation continues
to evolve. For example, IT administrators are examining
new uses for virtual desktops, in which employees use
their desktop, laptop, tablet, or smartphone to access
to a virtual machine running on a server. Many core
applications and data are accessed through this virtual
desktop, giving the IT department more of an ability to
control access to corporate systems.
Issues With Virtualisation
The change to IT operations can be a benefit, but it is
also an area of concern. Decoupling applications from
physical machines leads to greater efficiencies, but it also
requires a new knowledge of Virtualisation techniques
and a new mindset towards compute resources. There will
be a learning curve for IT administrators coming from a
traditional environment, and there will also be education
needed for end users.
There is also a learning curve involved in understanding
the best use of Virtualisation. There are performance
considerations in consolidating resources. Workloads
have to be analysed, and certain applications—such as
SQL databases and Voice over IP (VoIP)—should be
carefully examined to determine if they are Virtualisation
candidates. Administrators will need to ensure that peak
demands can be met as applications are sharing the
resource pool and that applications do not suffer from
being virtualised.
In restructuring an IT department to handle virtual
machines, the policies will also have to be addressed.
Virtual machines are simpler to bring up than physical
machines, but this can lead to a proliferation of machines
that is hard to manage. Some companies store images for
starting up virtual machines to save the time involved in
configuring the machine for specific applications. These
images also must be tracked and maintained.
Security is one of the most important policies to address.
The hypervisor adds a layer of software to the operational
stack, which in turn adds vulnerabilities. There must be
a plan for the security of each machine—including the
host machine and all virtual machines. Communications
between machines also must be monitored, and in the
case of virtual machines on a single host talking to
each other, this communication does not have external
components that can be monitored. Existing security
policies will need to be modified to handle these issues,
and additional tools may be required to secure the virtual
infrastructure.
Compliance must also be monitored in a virtual
environment. A single host may have a virtual machine
with PCI information and other virtual machines without
that information. This is allowed by the regulations, but
additional care is needed to ensure that data does not
cross the virtual machine boundaries.
Finally, a new focus on Virtualisation techniques
should not come at the cost of managing the physical
infrastructure. There are benefits to consolidation, but
it also means that host machines become more critical
as they support multiple applications. It is worthwhile to
revisit policy related to monitoring physical resources and
ensuring redundancy.
These issues are not insurmountable. There are a wide
variety of vendors and service providers who can assist
with these areas. However, dealing with these issues adds
to the cost of Virtualisation. It may be simple to calculate
how many physical servers can be removed by virtualising
or how much energy is saved, but the additional costs of
training and policy changes must be taken into account.
For this reason, calculating ROI on Virtualisation is not
a trivial matter. In a general sense, the economics of
Virtualisation are a net benefit to companies. But it is up
to individual firms to assess their Virtualisation strategy
and lay out the proper investment plan.

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Getting Started With Virtualisation
For those companies who have not yet virtualised their
compute resource, Virtualisation may still be a good step
to take prior to considering cloud solutions. This will give
some experience with virtual environments that may prove
beneficial when dealing with cloud issues. As with all IT
projects, a thorough plan is the best path for success.
1. Understand your workloads. Server consolidation will only
be effective if there are a sufficient number of underutilised
servers running similar workloads. Administrators can
start by monitoring performance loads to understand the
peak demand for resources. Next, applications should
be examined. Applications that require very low latency
are still in the early stages of being virtualised and may
not be ideal candidates. There is no exact formula for
determining how to virtualise, but best practices can
guide administrators who are examining their data centre.
Whether the Virtualisation initiative is being driven from
within the IT department or from the executive level,
this initial step is critical in assessing the feasibility of
Virtualisation.
2. Build the business case. This may be less critical if the
push for Virtualisation is coming from executives, but
IT administrators hoping to convince management to
invest will need to have a thorough analysis. All costs
should be carefully considered, from hardware and
software to training and time. Less tangible items such as
organisational flexibility should be included in the list of
benefits.
3. Train the staff. Once the plan is approved, IT staff will
need to begin building their knowledge and skills. Many
vendors offer training modules, and there are also a wide
range of consultative resources to consider. Certification
in Virtualisation can ensure that staff members are up to
speed on the most recent trends and best practices.
4. Examine IT policies and plans. Policies surrounding
security and compliance will have to be modified for a
virtual environment. Even policies related to the physical
machines will have to be addressed, since there is now
a greater dependence on a host running several virtual
machines. In addition, plans such as disaster recovery and
business continuity will now take advantage of the virtual
infrastructure. This is a good time to involve other lines of
business in the Virtualisation planning.
5. Start small. Attempting to virtualise as much infrastructure
as possible in the first iteration is likely to lead to mistakes
and higher costs. Virtualisation can be approached in
stages, which will give time for any issues to be resolved,
support structures to be put in place, and familiarity with
management tools to be built. Small implementations of
less critical applications provide learning opportunities for
larger implementations in the future.
6. Monitor and adjust as needed. Virtualisation is not a
project with a defined end date. Instead, it is a new way of
operating IT, and as such it will be constantly adjusted as
with any business process. In addition to becoming more
adept at the technical aspects of Virtualisation, the IT
department can continue to learn more about the various
lines of business and how they use IT. This will give insight
as to how to optimise the virtual environment.
Though not every customer has sufficient computer resources
to benefit from a Virtualisation transition, knowing more
about the technology, the benefits, and the drawbacks will
help customers make educated decisions. As Virtualisation
continues to extend beyond servers into other functions,
solution providers and end users both will continue to find
innovative ways of operating in a virtual environment.
Taking Virtualisation Knowledge
Into the Cloud
• Those IT departments who maintain responsibility for server
maintenance can eventually move towards a private cloud
environment as automated resource management and self-
service provisioning are added to the virtualised solution.
• Public cloud users can ask their cloud providers about
the details of the virtual environment. Issues such as
security and restoration of service will depend on the
Virtualisation implementation, and users of Infrastructure
as a Service (IaaS) and Platform as a Service (PaaS) will
be provisioning and working on virtual machines.

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Appendix
Virtual Machine Virtual Machine
A virtualisation layer allows virtual machines, possibly with different operating systems,
to be created within the live operating system running on the host machine.
App App
OS1 OS2
Virtualisation Layer
OS
Hardware
App App
App App App
App App
Hosted Virtualisation
Container Container
The OS virtualisation layer creates separate containers,
all running the same operating system. These environments
run on the same base OS and hardware, but allow for individual processes and users
App App
OS1 OS2
OS Virtualisation Layer
OS
Hardware
App App
App App App
App App
OS Virtualisation

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