Virtualization
Technologies
Hugo Valentim m6104
Nuno Pereira m6691
Rafael Couto m6027
Outline: Virtualization Technologies
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Introduction
Making a Business Case for Virtualization
Virtualization Technologies
Virtualization Applications
Performing a Server Virtualization Cost-Benefit Analysis
Nine Steps to Your First Virtualization Project
Five Virtualization Pitfalls to Avoid
References
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Virtualization- A Manager’s Guide
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Virtualization for Dummies
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By Dan Kusneztky, O’Reilly – ISBN: 978-1-449-30645-8
By Bernard Golden, Wiley Publishing Inc. – ISBN: 978-0-470-14831-0
Server Virtualization – Cloud Computing
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By C. Y. Huang, Department of Computer Science – National Tsing Hua University
Introduction
Virtualization: A Definition
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Operating system virtualization is the use of software to allow a piece of hardware
to run multiple operating system images at the same time.
The technology got its start on mainframes decades ago, allowing administrators
to avoid wasting expensive processing power.
There are three areas of IT where virtualization is making head roads, network
virtualization, storage virtualization and server virtualization.
Network virtualization
• Is a method of combining the available resources in a network by splitting
up the available bandwidth into channels, each of which is independent
from the others, and each of which can be assigned (or reassigned) to a
particular server or device in real time.
Storage virtualization
• Is the pooling of physical storage from multiple network storage devices
into what appears to be a single storage device that is managed from a
central.
• Storage virtualization is commonly used in storage area networks (SANs).
Server virtualization
• Is the masking of server resources from server users. The intention is to
spare the user from having to understand and manage complicated details
of server resources while increasing resource sharing and utilization and
maintaining the capacity to expand later.
Why Virtualization Is Hot right now?
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Hardware is underutilized
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Data centers run out of space
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Energy costs go through the roof
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System administration costs mount
Types of Virtualization
• Operating system virtualization (containers)
• Hardware emulation/Full Virtualization
• Para-virtualization
Operating system virtualization (containers)
• Multiple versions of the same app running at the same time
• Split of IO devices into the containers
• Web Servers
Hardware emulation/Full Virtualization
• Guest OS has all the hardware
• Bootcamp
Para-virtualization
• Main OS control the access of all guest OS to the hardware
• Main OS control all the needs for the guest OS
• Guest OS know that its virtualized
Making a Business Case
for Virtualization
Making a Business Case for Virtualization
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You’re drowning in servers.
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You need to use your hardware more efficiently.
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You need to reduce energy costs.
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You need to make IT operations in general more efficient.
Virtualization Lowers Costs
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Total number of server machinery can be lower
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Less power consumption
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Less problems with maintenance
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Simple control of servers and hardware
Software Costs: A Challenge for
Virtualization
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When it comes to virtualization, software licensing is a mess.
Oracle has taken the position that its fee should be based on the total number of
processors in the server.
End users are confused about their licensing rights and responsibilities in a
virtualized environment, and the situation appears to be driven more by vendor
business needs rather than by customer satisfaction.
Virtualization
Technologies
Full Virtualization
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Full Virtualization is a virtualization in which the guest operating system is
unaware that it is in a virtualized environment, and therefore hardware is
virtualized by the host operating system so that the guest can issue commands to
what it thinks is actual hardware, but really are just simulated hardware devices
created by the host.
Paravirtualization
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Paravirtualization is a virtualization technique in which the guest operating
system is aware that it is a guest and accordingly has drivers that, instead of
issuing hardware commands, simply issues commands directly to the host
operating system.
Full Virtualization Vs. Para-Virtualization
Nested Virtualization
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Is simply a VM running inside another
VMExample: A Windows 8 VM running a ubuntu VM.
Hybrid Virtualization
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This virtualization technique is a combination of Paravirtualization and Full
Virtualization, where parts of the guest operating system use paravirtualization
for certain hardware drivers, and the host uses full virtualization for other
features. This often produces superior performance on the guest without the need
for it to be completely paravirtualized.
An example of this: The guest uses full virtualization for privileged instructions in
the kernel but paravirtualization for IO requests using a special driver in the guest.
Hardware emulation
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Hardware Assisted Virtualization (emulation) is a type of Full Virtualization where
the microprocessor architecture has special instructions to aid the virtualization of
hardware. These instructions might allow a virtual context to be setup so that the
guest can execute privileged instructions directly on the processor, even though it
is virtualized.
If said instructions do not exist, Full Virtualization is still possible, however it must
be done via software techniques such as Dynamic Recompilation where the host
recompiles on the fly privileged instructions in the guest to be able to run in a nonprivileged way on the host.
Examples: Console emulators
OS Virtualization
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Operating-system-level virtualization is a virtualization method where the kernel
of an operating system allows for multiple isolated user space instances, instead
of just one. Such instances (Ex. Containers) may look and feel like a real server
from the point of view of its owners and users.
Operating-system-level virtualization usually imposes little to no overhead,
because programs in virtual partitions use the operating system's normal system
call interface and do not need to be subjected to emulation or be run in an
intermediate virtual machine, as is the case with whole-system virtualizers.
This form of virtualization also does not require support in hardware to perform
efficiently.
OS Virtualization (Cont.)
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This virtualization is not as flexible as other virtualization approaches since it
cannot host a guest operating system different from the host one, or a different
guest kernel. For example, with Linux, different distributions are fine, but other
operating systems such as Windows cannot be hosted.
Some operating-system-level virtualization implementations provide file-level
copy-on-write mechanisms. This means that a standard file system is shared
between partitions, and those partitions that change the files automatically
create their own copies. This is easier to back up, more space-efficient and simpler
to cache.
OS Virtualization
https://www.youtube.com/watch?v=NQSIWo8mXFE
Storage Virtualization
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Storage virtualization is the fusion of multiple network storage devices into
what appears to be a single storage unit. Storage virtualization is usually
implemented via software applications and often used in SAN (storage
area network), making tasks such as archiving, back-up, and recovery
easier and faster.
Storage Virtualization (Ex.)
Network Virtualization
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When applied to a network, virtualization creates a logical software-based
view of the hardware and software networking resources (switches, routers,
etc.).
The physical networking devices are simply responsible for the forwarding
of packets, while the virtual network (software) provides an intelligent
abstraction that makes it easy to deploy and manage network services and
underlying network resources.
Network Virtualization(Ex.)
Applications Virtualization
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Application virtualization is software technology that encapsulates application
software from the underlying operating system on which it is executed.
A fully virtualized application is not installed in the traditional sense, although it is
still executed as if it were.
The application behaves at runtime like it is directly interfacing with the original
operating system and all the resources managed by it. In this context, the term
"virtualization" refers to the artifact being encapsulated.
Desktop Virtualization
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Desktop virtualization is software technology that separates the desktop environment and
associated application software from the physical client device that is used to access it.
Desktop virtualization can be used in conjunction with application virtualization and user
profile management systems, to provide a comprehensive desktop environment
management system.
In this mode, all the components of the desktop are virtualized, which allows for a highly
flexible and much more secure desktop delivery model. In addition, this approach supports
a more complete desktop disaster recovery strategy as all components are essentially
saved in the data center and backed up through traditional redundant maintenance
systems.
Desktop Virtualization
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If a user's device or hardware is lost, the restore is much more straightforward and
simple, because basically all the components will be present at login from another
device. In addition, because no data is saved to the user's device, if that device is
lost, there is much less chance that any critical data can be retrieved and
compromised.
Virtualization Applications
Development and Testing
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Engineer's build some software to implement certain functionality's. Depending
on the type of software, it might need to run on more than one operating system
(say, on Linux and Windows).
After the engineer has built the software to run in those environment, the
software is handed off to a testing group to ensure quality.
Test groups often do things like inputting data of the wrong type or feeding-in a
data file of the wrong format, all to see whether the software is likely to work in
real-world usage conditions. One consequence of this kind of destructive testing is
that it tends to crash machines and often wipes out the operating system,
necessitating a fresh install of the OS and application before any additional
testing can be done.
Development and Testing
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There are a few problems with this situation, however:
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Only a portion of the development and test cycle requires multiple systems.
Most development and test work that is done on multiple machines is done only to
ascertain basic functionality; therefore, many of the machines are lightly loaded and
lightly exercised.
When development or testing causes a system crash, it can take time and labor to
reinstall everything to get ready for the next task.
Keeping a bunch of machines sitting around for occasional development or test work
requires space and cost money.
Development and Testing
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Nowadays Even a developer’s laptop is plenty powerful enough to support several guest
machines.
By using virtualization, a developer or tester can replicate a distributed environment
containing several machines on a single piece of hardware.
This setup negates the need to have a bunch of servers sitting around for the occasional use
of developers or testers. It also avoids the inevitable conflict that occurs when an
organization attempts to have its members share machines for distributed use.
This capability is a boon to developers and testers. Rather than having to repeatedly rebuild
test instances, they can just save a complete virtual machine image and load it each time
they trash a virtual machine instance. In terms of recovery time, the consequences of a
machine crash go from hours to minutes.
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Training(Teaching)
Training is a common application of virtualization. Because technical training requires that students
have a computer system available to experiment and perform exercises on, the management of a
training environment has traditionally been very challenging and labor intensive.Training typically
tracks the following scenario:
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1. The student begins with a basic technology setup.
2. The student performs set exercises involving more and more complex operations, each of
which extends or modifies the basic technology setup.
3. At class end, the student leaves the course having successfully completed all exercises and
having significantly modified the basic technology setup
The challenge then faced is the need to restore the environments back to the basic setup. With
virtualization, the restoration process is quite simple. For instance if hardware emulation or
paravirtualization is being used, the virtual machines used by the last batch of students are deleted
and new virtual machines are created from images that represent the desired starting point. Now
setting up training environments has gone from hours or days to minutes.
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Server Consolidation
Consolidation is the act of taking separate things and creating a union that
contains all of them.
With respect to virtualization, consolidation refers to taking separate server
instances and migrating them into virtual machines running on a single server. It
addresses the problems most folks desperately want virtualization to address:
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underutilization of servers in the data center;
server sprawl that threatens to overwhelm data center capacity;
sky-high energy costs from running all those underutilized servers;
Escalating operations costs as more system administrators are required to
keep all those underutilized servers humming.
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Server Consolidation
A typical server consolidation project accomplishes the following:
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1. Identifies a number of underutilized systems in the data center.
2. Selects one or more servers to be the new virtualization servers; these might be
existing or newly purchased.
3. Installs virtualization software on the new virtualization servers.
4. Creates new virtual machines from the existing servers.
5. Installs the new virtual machines on the new virtualization servers.
6. Begins running the virtual machines as the production servers for the applications
inside the virtual machines.
Companies implementing server consolidation often move from running 150 physical
servers to running 150 virtual machines on only 15 servers, with an understandable
reduction in power, hardware investment, and employee time.
Failover
• Companies run many applications that they consider mission critical. Running
applications on a single server exposes the company to a single point of failure
(referred as SPOF).
• Failover technology essentially mirrors one copy of the application to a second
machine, and it keeps them consistent by constantly sending messages back and
forth between the copies. If the secondary machine notices that the primary
machine is no longer responding, it steps up to the plate and takes on the workload
when one system goes down, the application does a failover to the secondary
system. Although this functionality is clearly critical, it’s important to note some
less-than-desirable aspects to it:
Failover
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It’s application specific. If every mission-critical application provides its own
method of achieving failover, the IT operations staff has to know as many different
technologies as there are applications. This is a recipe for complexity and high cost.
It’s wasteful of resources. Keeping a mirrored system up for every mission-critical
application requires a lot of extra machines, each of which imposes its own
operations costs, not to mention being wasteful of a lot of extra hardware.
Furthermore, because one of the factors driving the move to virtualization is that
data centers are overfilled with machines, a solution that requires even more
machines seems undesirable.
It’s expensive. Every vendor recognizes that failover is mission critical, so it charges
a lot for the functionality.
High Availability
• High availability extends the concept of simple failover to incorporate an
additional hardware server.
• Instead of a crashed virtual machine being started on the same piece of
hardware, it is started on a different server, thereby avoiding the problem of
a hardware failure negating the use of virtualization failover.
• But how does it work?
• How can a hypervisor on one physical server start a virtual machine on
another hypervisor?
• It can’t.
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High Availability
High availability relies on an overarching piece of virtualization software that coordinates
the efforts of multiple hypervisors.
When a virtual machine on one hardware server crashes, the coordinating software starts
another virtual machine on a separate hardware server.
The coordinating virtualization software is constantly monitoring all the hypervisors and
their virtual machines. If the coordinating software sees that the hypervisor on one server is
no longer responding, the software then arranges to start any virtual machines that were on
the failed hardware on other hardware.
So HA addresses the issue of hardware failure by using higher-level virtualization software
to coordinate the hypervisors on two or more machines, constantly monitoring them and
restarting virtual machines on other machines if necessary.
This setup certainly addresses the issue of hardware failure and makes the failover solution
more robust.
Load Balancing
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Simply put, load balancing involves running two instances of a virtual machine on
separate pieces of hardware and dividing the regular workload between them.
By running two instances of the virtual machine, if one machine crashes, the other
continues to operate. If the hardware underneath one of the virtual machines fails,
the other keeps working. In this way, the application never suffers an outage.
Load balancing also makes better use of machine resources. Rather than the
second VM sitting idly by, being updated by the primary machine but performing
no useful work, load balancing makes the second VM carry half of the load, thereby
ensuring that its resources aren’t going unused. The use of duplicate resources can
extend beyond the virtual machines.
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Load Balancing
Virtualized storage is a prerequisite for load balancing because each virtual
machine must be able to access the same data, which is necessary because
application transactions can go to either virtual machine.
In fact, depending on the application and how the load balancing is configured,
transactions might go through both virtual machines during the execution of an
extended transaction. Therefore, both machines must be able to access the data,
and therefore, virtualized storage is required.
We can also configure load balanced virtual machines to act as clustered machines
and share state between them. That way, if a virtual machine crashes, the other
can pick up the work and continue it.
Load Balancing
www.youtube.com/watch?v=oEcEqN8PeeI
Server pooling
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Now you’re probably thinking “Wow, virtualization sure can be applied in a
lot of useful ways, but there seems to be a lot of installing and configuring.
Wouldn’t it be great if the virtualization software was arranged for the
installation and configuration so that I automatically got failover and load
balancing?”
Server pooling
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In fact, that functionality exists.
It’s called server pooling, and it’s a great application of virtualization. With server pooling, a
virtualization software manages a group of virtualized servers. Instead of installing a virtual machine
on a particular server, the administrator merely point the virtualization software at the virtual
machine image, and the software figures out which physical server is best suited to run the machine.
The server-pooling software also keeps track of every virtual machine and server to determine how
resources are being allocated.
If a virtual machine needs to be relocated to better use the available resources, the virtualization
software automatically migrates it to a better-suited server.
The pool is managed through a management console, and if the administrator notices that the
overall pool of servers is getting near to the defined maximum utilization rate, he can transparently
add another server into the pool. The virtualization software then rebalances the loads to make the
most effective use of all the server resources.
Server pooling
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Because there is no way of knowing which physical server will be running a virtual
machine, the storage must be virtualized so that a VM on any server can get access
to its data.
Most IT organizations haven’t moved toward server pooling, yet. Server pooling
and Distributed Resource Scheduler, in addition to intelligently moving and
migrating machines to other machines that have more resources (load balancing),
help with moving machines when a hardware failure hits. So, rather than using
clustering for failover, Distributed Resource Scheduler can help move a machine
when its base hardware has an issue.
Server pooling
• https://www.youtube.com/watch?v=yGX2QLutpdM
Disaster recovery
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Disaster recovery comes into play when an entire data center is temporarily or
permanently lost.
In complete data center loss, IT organizations need to scramble to keep the
computing infrastructure of the entire company operating. Virtualization can help
with the application recovery and ongoing management tasks. Any of the failover,
High Availability, load-balancing, or server-pooling virtualization capabilities may
be applied in a DR scenario.
Their application just depends on how much you want to physically manage during
the DR process. Because virtual machine images can be captured in files and then
started by the hypervisor, wich makes virtualization an ideal technology for DR
scenarios.
Disaster recovery
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In a time of a disaster, needing to locate physical servers, configure them, install
applications, configure them, and then feed in backup backups to get the system up to
date is a nightmare.
Keeping spare computing capacity in a remote data center that completely mirrors your
primary computing infrastructure is extremely expensive.
With virtualization, a much smaller set of machines can be kept available in a remote data
center, with virtualization software preinstalled and ready to accept virtual machine
images.
In the case of a disaster, such images can be transferred from the production data center to
the backup data center. These images can then be started by the preinstalled virtualization
software, and they can be up and running in just a few minutes.
Disaster recovery
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Because virtualization abstracts hardware, it is possible to move a virtual machine from one
hypervisor to another, whether the hypervisors are on machines in the same rack or on
machines in data centers halfway around the world from one another.
Because the virtual machines can be moved to any available hypervisor, it is possible to
more easily implement a disaster recovery plan, with no need to replicate an entire data
center.
Example: The Hurricane Katrina: When it struck, many IT shops lost all processing
capability because their entire data centers were inundated. If that weren’t enough,
Internet connectivity was lost as well due to telecommunications centers being flooded.
Performing a Server
Virtualization Cost-Benefit
Analysis
Looking at current costs
• Most IT organizations don’t track their costs with much granularity;
• Almost impossible to request a report that shows the current costs of the
infrastructure to be virtualized;
• However it is possible with a bit of work, create a fairly accurate estimate of
the current cost of the infrastructure;
• There are two broad categories: hard costs and soft costs.
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Easier to document hard costs rather than soft costs.
Hard Costs
• Any costs that require paying actual money to an entity.
• Usually associated with a specific product and service.
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E.g., an outside company to run security scans on the servers.
Hard Costs Examples
• Power – obvious!
• Server Maintenance - covers maintenance on machines;
• Outside Services - outside vendors for anything associated with keeping its
infrastructure up and running (for example, someone to run backups on the
machines).
Soft Costs
• Are typically associated with internal personnel or internal services for
which no explicit chargeback system is in place;
• Soft costs are what the organization spends on an ongoing basis doing its
daily work.
• Very few organizations systematically keep track of the specific tasks its
members perform, as well as the amount of time its members devote to
each task.
Soft Costs Examples
• Machine Administration - refers to the work done by internal personnel
keeping the technology infrastructure humming;
• Backup - refers to the process of creating a secure copy of the data on
individual machines;
Identifying virtualization costs
• After establishment of the current running costs of the infrastructure as-is,
it is important to understand the potential benefits and costs of moving to
virtualization;
• It requires estimation rather than documentation;
Selecting a VirtualizationDeployment Scenario
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The first step is to define the configuration you’ll most likely install.
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For example: individual virtualized servers or a virtualized pool of servers, possibly including
virtualized storage, as well.
Without a defined configuration, you can’t accurately estimate the cost of moving to
virtualization.
One will incur a range of costs as moving to virtualization, and it’s important to recognize
them and estimate them in the overall cost-benefit analysis.
Identifying New Hardware Needs
• Virtualization is a very flexible technology and is capable of running on a
very wide range of hardware;
• Bringing in new hardware as part of the virtualization project might make
good sense;
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Those costs need to be added to the cost analysis.
• If current hardware is in good condition, one should consider creating two
versions of the cost analysis: one with new hardware and one without;
Considering Other Physical Equipment
• Depending on the envisioned configuration, one might also decide to
include other physical equipment such as Network-Attached Storage or a
Storage Area Network.
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Any additional physical equipment is, naturally, a hard cost and should be documented
in that section of the detail spreadsheet.
• Software licenses might also be required to implement other physical
equipment, so one might need to estimate and document an additional
hard cost in the new software section of the worksheet.
Purchasing New Software
• Software licenses are a hard cost
• Depending on the load generated on the physical hardware, one will be able
to estimate how many virtual machines one can support per physical
machine.
• Presenting an annualized view is important because software licenses
typically carry a significant cost in Year One and then a lower ongoing cost
for software maintenance and licensing.
Training Employees
• A learning curve is associated with beginning to use any new software
product;
• Many organizations educate their employees through crash-courses;
• These training costs should be contemplated in implementation costs.
Identifying the financial benefits of
virtualization
• After the definition of the configuration and associated costs of the
virtualization solution, one can estimate the financial benefits of the
migration.
• There are two types of financial benefits by moving to virtualization:
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Cost savings through not having to spend money one is currently spending on the
existing infrastructure;
Cost savings through more effective and efficient operations.
Reduced Hard Costs
• Reduced hardware maintenance: as there are fewer machines, the hardware
maintenance bill will shrink;
• Reduced software licenses: one might be able to realize savings on software
licenses, as some vendors charge per physical device and not per “machine
itself”;
• Reduced power cost: fewer machines = less power consumption;
Reduced Soft Costs
• System administration work is reduced: there are reduced worries about
hardware failure, and less work on maintenance as “everything” is managed
by itself.
• Soft costs might require rough estimates: estimating reduced work is
difficult, so it is better to make rough predictions.
Creating a Cost-benefit Spreadsheet
• Three sheets:
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Current cost structure;
Virtualized cost structure;
Project cost summary
Creating a Cost-benefit Spreadsheet (cont.)
• Important sections:
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Financial implications across time;
Separated hard and soft costs sections;
Summary worksheet must really summarize the big picture;
Creating the spreadsheet with both detail and summary worksheets ensures that one
have captured all the costs of the two options.
Nine Steps to Your First
Virtualization Project
Evaluate Use Cases
• Don’t think shortsighted;
• They must reflect what your virtualization identity should be;
• They must reflect the opinions/recommendations one have collected from
the company employees;
Review of Organizational Ops. Structure
• Virtualization isn’t only a technical issue, it’s also political;
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People need to be willing to adapt to it;
• Take into account there might be groups within the company that use
computational resources differently;
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A group may use only windows machines and another may use only linux machines;
Define the Virtualization Architecture
• Merge use cases and insights gathered from the organizational structure;
• This is critical and should be reviewed within the organization
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It ensures that it captures everyone’s needs;
Generates awareness and commitment from the different interviewed groups.
Select the Virtualization Product(s)
• It must be a straightforward process has it should be clear from the
virtualization architecture;
• Be aware: although a product’s website might claim that it can do such-andsuch a function, the actual implementation of that functionality might only
work well enough for the vendor to claim support for it, but not that well in
real-world use.
Select the Virtualization Hardware
• Final check on existing hardware;
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If possible and worthy keeping existing hardware will lower initial capital investment;
• There are machines specifically designed for virtualization;
Perform a Pilot Implementation
• Creates the opportunity to determine if the designed virtualization
architecture will work;
• It should replicate on a small scale the final system run, including:
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Hardware, software, applications and workloads.
Implement the Production Environment
• Phase to:
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Order software and hardware;
Install any necessary data center equipment (for example, power connections);
Install the virtualization software and hardware;
One is ready to move forward with migration to the new virtualized architecture.
Migrate the Physical Servers
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Automated
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Automated migration software products are available, which are usually called physical-tovirtual migration tools - P2V tools; Better for Windows based systems rather than Linux
systems.
Manual
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Hands-on work to move systems. It consists in installing software in a new virtual machine,
backing up the data from the existing physical server, and then recovering that data into the
new virtual server.
Manage the Virtualized Infrastructure
• There is always work to be done:
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Tunning;
Management;
And so on….
Five Virtualization Pitfalls
to Avoid
Don’t Skip on Training
• Typical error of organizations;
• There is always a learning curve associated with new technologies.
Don’t Apply Virtualization in Areas That Are
Not Appropriate
• High loaded systems are not candidates to be virtualized;
• Critical systems are also not candidates to be virtualized;
• Low load systems are good candidates because they will optimize hardware
utilization.
• It is important to evaluate the purpose and load of the systems to be
virtualized.
Don’t Imagine That Virtualization Is Static
• Periodic examinations of the current solution in light of what’s newly
available.
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It may be worth to upgrade the systems (hardware and/or software).
• It’s part of the virtualization management tasks.
Don’t Skip the “Boring” Stuff
• It is important to do the use cases and the architecture design reviews
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Without them important directives may get forgotten;
Don’t Overlook the Importance of Hardware
• It is greatly possible that the current hardware isn’t suitable for
virtualization, or at least not optimized;
• The importance of hardware is only going to increase as new, virtualizationready hardware comes to market.
Q&A
Hugo Valentim m6104
Nuno Pereira m6691
Rafael Couto m6027
Quiz Time!