4. Virtualization is abstracting the hardware to run
virtual instances of multiple guest operating systems
on a single host operating system.
You can see Virtualization in action by installing
Microsoft Virtual PC, VMware Player or Sun
VirtualBox.
These are desktop virtualization solutions that let you
install and run an OS within the host OS.
5. There are many reasons for running Virtualization on
the servers running in a traditional data center. Here
are a few:
Meantime to Restore
Maximizing the server utilization
Reduction in maintenance cost
Efficient management
6. Virtualization on the Server
Typically the OS is designed to act as an interface
between the applications and the hardware.
It is not specifically designed to run the guest OS
instances on top of it.
7. In the server virtualization scenario, the host OS is not
very significant.
OS is not ideal for running multiple VMs and has a
little role to play, there is a new breed of software
called Hypervisor that takes over the OS.
8. Hypervisor is an efficient Virtual Machine Manager (VMM)
that is designed from the ground up to run multiple high
performance VMs. So, a Hypervisor is to VMs what an OS is
to processes.
A Hypervisor can potentially replace the OS and can even
boot directly from a VM. This is called bare metal approach
to virtualization.
These Hypervisors have low footprint of few megabytes
(vmWare ESXi is just 32MB in size!) and have an embedded
OS with them.
9. Hypervisors are assisted by the hardware
virtualization features built into the latest Intel and
AMD CPUs.
This combination of hardware and Hypervisor turns
the server into a lean and mean machine to host
multiple VMs.
10. The VM that is used by the Hypervisor to boot as a
host is called a paravirtualized VM.
This concept makes virtualization absolutely
powerful.
Imagine a server booting in few seconds and the
required paravirtualized (host) VM gets copied over a
gigabit Ethernet to run multiple guest VMs.
This turns the datacenter to be very dynamic and
agile.
11. Citrix XenServer
Xen’s paravirtualization technology is widely
acknowledged as the fastest and most secure
virtualization software in the industry and it is
enhanced by taking full advantage of the latest Intel®
VT and AMD-V™ hardware virtualization assist
capabilities.
It is free.
12. VMware ESXi
This product is another bare metal Hypervisor from
the virtualization leader, VMware. This is one of the
best Hypervisors with just 32MB footprint.
ESXi ships with Direct Console User Interface (DCUI)
that provides basic UI required for administering and
managing the Hypervisor.
13. Microsoft Hyper-V Server
This is a free Hypervisor from Microsoft based on the
same Hypervisor that ships with Microsoft Windows
Server Hyper-V edition.
This is best suited for Virtual Desktop Infrastructure
(VDI) because of its compatibility with Windows Vista
and Windows 7. Hyper-V does not have any local GUI
but can be managed from System Center Virtual
Machine Manager (SCVMM).
15. Elasticity
We know that the key attribute of the Cloud is
Elasticity, which is the ability to scale up and scale
down on the fly.
This capability is achieved only through virtualization.
Scaling up is technically adding more server VMs to an
application and scaling down is detaching the VMs
from the application.
16. Self Service
The Hypervisor comes with an API and the required
agents to manage it remotely. This functionality can
surface through the Self Service portals that the
Cloud vendor offers.
So, when you move a slider to increase the number of
servers in your web tier, you are essentially talking to
the Hypervisor to action that request.
17. Pay-By-Use
By leveraging the management and monitoring
capabilities of the Hypervisor, metering the usage of
resources like the CPUs, RAM and storage can be
easily achieved.
18. Programmable Infrastructure
Developers can directly talk to the Hypervisor
through the native APIs or Web Services exposed by
the Cloud vendors.
Through this, they can take the control of the VMs.
It is very obvious that the Cloud is heavily relying on
virtualization and efficient Hypervisors to achieve its
goal.
20. Most of the Cloud providers give you an option to
host your application at a specific location.
Depending on the customer base and the expected
user location, you can choose a location.
This will ensure that all your components like storage,
compute and database services are hosted within the
same data center.
This will reduce the latency and makes the application
more responsive Geographically.
22. Data Center
A Cloud Data Center runs
hundreds of Servers
Your app will be deployed at a data center physically
located at a place that you have chosen.
These data centers typically run thousands of
powerful servers that offer a lot of storage and
computing power.
23. Server
You never know which physical server is responsible
for running your code and the application.
In most of the cases, the app that you deployed may
be powered by more than one server running within
the same data center.
Servers are treated as a commodity resource to host
the VMs. There is no affinity between a VM and a
physical server.
24. Virtual Machine
This is the layer that you will directly interact with. In
Platform as a Service (PaaS), you may not realize that
you are dealing with a VM but in reality most of the
Cloud implementations will host your code or app on
a VM.
Load balancer which will ensure that your
applications are scalable by exploiting the power of
all the VMs associated with your application.
