A plus 220-1001 – Exam Objective 4.2 – Dumps4shared

A plus 220-1001 – Exam Objective 4.2

A+ Exam Objective 4.2

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4.2 Given a scenario, set up and configure client-side virtualization.

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Welcome to ExamNotes by CertBlaster! In
this section, we will look at virtualization, the ability to do more with less.
Multiple tasks that once took multiple machines to perform can now be done by
one machine’s processing power. This process is called virtualization and can involve
two methods. Server-side virtualization (Type 1)
occurs when all of the processing is handled by the server which in-turn delivers
virtual environments or machines to each client. Client-side virtualization (Type
2
) occurs when the client desktops are virtualized into multiple
machines. In both cases, the virtual machines operate in their own isolated
space where their OS is installed on software which is used to emulate physical
hardware.

Purpose of virtual machines

The purpose of virtual machines (VMs) is multi-layered.
Primarily, virtualization maximizes the resources available. No additional
physical resources are required for each virtual machine such as keyboards,
mice, and monitors. This reduces energy consumption and also lowers overall
heat generation. Another very stabilizing aspect of using the virtual
environment is that since the entire machine is now essentially software, it is
easier to backup and much easier to transport. There is no hardware to
transport and only the set of files, including the VHD (Virtual Hard Disk), is
required for transportation.

Virtual machines are run on software that emulates a
customizable, physical hardware environment and supports the installation and
operation of multiple operating systems. This is beneficial in application
testing where a single physical machine can support Windows, OS X, and Linux
systems, providing a reliable operational environment to evaluate the products.
This configuration also enables the user to run an older application, for
example one that requires Windows XP, by installing it on a virtual Windows XP
machine.

Classifications for Virtual Machines depend on the processing
power of the client and are as follows:

Zero client – this is essentially a
“dumb terminal” and consists of a keyboard, mouse, monitor, and network interface.
There is no operating system and this type uses complete server-side
virtualization.

Thin client – this client does little
to no processing but does have enough resources to barely support an operating
system. This type relies on the server to do all of the processing.

Thick / Fat client – this is a fully
functional workstation PC or portable device that is entirely self-sufficient
and will access the server only when necessary.

Resource requirements

Resource requirements for hypervisors, or Virtual Machine
Monitors (VMMs), depend on the scale, number of virtual machines (or instances)
to be deployed, the anticipated number of users, and the type of hypervisor
being used. The VMM allocates a specified amount of Processor cores, memory,
and hard disk space to each virtual machine instance. There must be sufficient
resources to support the host operating system, the VMM, and the VMs to be deployed.

Shown below is an example of a generous allotment of Processor, memory,
and disk space which has been dedicated to a VM. Note the memory allocation and
remember that the 64-bit version of Windows 8 only requires 2 GB of memory. The
additional Processor, memory, and disk space can then be used to support more
users. The VMM captures these resources when this example VM is running.

Virtual Machine settings

The VMM controls the total amount of memory available for all
VMs while leaving sufficient resources for the host. You should not run a VM
below its system requirements or above an amount that is supportable by the
host as performance will suffer. This particular host has a 6 core processor
and 16 GB of memory. With a host requirement of 2 GB and a 2 TB hard disk, there
is plenty of room for a single VM instance. As you enable each VM instance,
less computing power is available to the host.

Emulator requirements

One thing is constant: the host system’s UEFI/BIOS must support
virtualization. Intel platforms use Intel VT and AMD platforms use AMD-V.
Without these enhancements, virtualization on the host is not possible. The
Emulator (VMM) must have access to enough resources in order to sufficiently cover
the host OS and any resource allocations due to the VMs.

Shown below is the same VM running alongside a Linux
installation that has 2 GB assigned. That’s 2 GB for the host, 2 GB for the Linux
instance, and 6 GB for the Windows install which equates to 10 GB total memory
usage.

VM Resource usage

In comparison at rest with no VMM enabled, the machine uses
roughly 30% of the Processor and 4.1 GB RAM.

Security requirements

Security requirements for VMs are particularly important because
new users tend to think that VMs are protected by the host’s
antivirus/antimalware software. This is not the case. Remember that virtual
machines are completely isolated from the host. Install the proper protection
packages on your VM and also realize that as a “machine,” separate software
licensing applies in most cases. Read your agreement carefully.

Network requirements

On a hosted VMM, you cannot consume more network bandwidth than
the host can support. For example, if you create instances of a Web server, an
FTP server, and a file server on the host machine and the instances experience
high network traffic, the host PC’s networking performance will fail since the
network bandwidth will be allocated to the running VMs. If the network traffic
is really high, the network performance of the VMs will also fail.

Hypervisor

Hypervisor is another term to identify the Virtual Machine
Manager (VMM). Hypervisors come in two types. Yes! That’s right! Type 1 and
Type 2.

Type 1 hypervisor (Bare
Metal) is installed on a clean machine with no operating system, typically a
server class machine in a multi-server environment. Compared to a conventional
operating system, this allows for more system resources to be dedicated to the
VMs due to the nearly nonexistent overhead. In order to remotely configure the
hypervisor, Type 1 hypervisors require a Management Console to be installed on
a separate physical machine. This external control is required due to the lack
of an operating system on the target hardware.

Type 1 hypervisor management consoles have the capability to
dynamically allocate resources. This is easily demonstrated in the case of RAM.
If you have 16 GB of RAM installed, dynamic allocation can support multiple VMs
configured with 16, 10, 8 and 4 GB of RAM for a total of 38 GB. The memory
resources are supplied to the VMs as needed, meaning that in most cases the
total requirement of the VMs will not exceed 16 GB and each virtual machine
will get what it needs at any particular time. If the memory capacity is
exceeded, the VM instance will be moved seamlessly and imperceptibly to a
server that can support it.

Type 2 hypervisor (Hosted)
is dependent on a host system’s operating system in order to run. The picture
below shows a Type 2 hypervisor installed on a Windows machine that is running
two VMs, one Linux and one Windows. In the left-pane, you can see the library
of available VMs.

Most type 2 hypervisors allocate all of the designated resources
upon the boot of each instance. It is quite possible to crash the host OS by
over-allocating resources. For example, consider we have multiple instances of
the same OS available and identically configured for testing. If we were to
turn them all on at the same time, the allocated resources would exceed the
available resources and the Host, as well as the VMs, would all crash. Be aware
of the finite nature of your resources and how your hypervisor type will
deliver them to the VM instances.

Type 2 Hypervisor

That’s all for 220-1002 Core 1 Objective 4.2. See you next time and good luck on the exam!

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