CNIT 242 Exam #2

Virtualization

running multiple systems simultaneously on one physical computer

System Virtualization

The process of emulating hardware so it can

be made available to multiple logical systems

True or False: Each system is independent of all others

True

A single computer (virtual server) appears as WHAT TYPE of computers to multiple client or guest

operating systems?

independent

Traditional vs virtualized

-Traditionally, hardware is dedicated to OS, on which applications run

-Virtualization software emulates hardware,

which guest OSes use as if real

When did virtualization start? and why?

Started by IBM in the 1960s to

partition large mainframe-based systems

When did virtualization stop? and why?

Abandoned in the 1980s - 90s. Due to inexpensive x86 servers and the popularity of

client/server applications

When did virtualization pick back up? and why?

Virtualization support for x86 systems was

started in 1998 by VMware to address server bloat.

Client Based (Hosted) Architecture

The virtualization layer is installed on top of an existing Operating System as an application

Client Based (Hosted) Architecture typically allows the best support for what host hardware?

Sound cards, USB ports, etc.

Another name for Client Based (Hosted) Architecture is...

Workstation virtualization

Which architecture if more efficient...Client Based(Hosted) Architecture or Bare-Metal(Hypervisor) Architecture?

Bare-Metal(Hypervisor) Architecture

True or False: Separate Operating System are required for Bare-Metal (Hypervisor) Architecture

False, No separate Operating System is necessary

Bare-Metal (Hypervisor) Architecture

Virtualization layer that is installed directly on the hardware

Virtual Machine(VM)

Each environment available for O/S installation

Guest Operating System

The operating system installed in a VM

Host Operating System

In a hosted architecture, the O/S in which the

virtualization software runs

Hypervisor

The software that provides the virtualization layer in a bare-metal architecture

Virtualization Advantages

-Flexibility

-Increased reliability

-Provides a consistent hardware interface regardless of the underlying physical

hardware

-Increased capacity and scalability

-Lower infrastructure costs

-Reduced energy costs

Virtualization Disadvantages

- Single point of failure

-Complicates hardware maintenance

-Harder to keep track of software and OSes

System Virtualization Components

-Full Virtualization

-Paravirtualization (aka - OS Assist)

-Hardware Assisted

-Memory Virtualization

-Device and I/O Virtualization

Full Virtualization

-Uses binary translation to execute instructions

that are non-virtualizable

-Offers the best isolation and most security

between VMs but is very complex

Paravirtualization (aka - OS Assist)

Uses a modified guest OS to remove

non-virtualizable instructions

hardware-assisted virtualization (HAV)

Hypervisor traps non-virtualizable instructions

and re-issues them to hardware in root mode,

which is a function of CPU enhancements

Memory Virtualization

Uses virtual to physical mappings maintained by the hypervisor

Device and I/O Virtualization

-Involves managing the routing of I/O requests between virtual devices and the shared physical hardware

-Biggest performance hit in system virtualization

System Virtualization Futures

-Virtualization will continue to be a key

technology through the foreseeable future

-Future development will likely

Client Based Virtualization Software

-Windows

-Macintosh

-Linux

Hypervisor Virtualization Software

-VMware vSphere

-Microsoft HyperV

-Xen

Why VMware?

Market leader, the most robust product offering, and Extensible.

Vmware Vsphere

a suite of software/services

What is in VMware Vsphere?

-Hypervisor (ESX, ESXi)

-vCenter Server

-VMotion and Storage Vmotion

-VMware DRS (Distributed Resource Scheduler)

-VMware HA (High Availability) and FT (Fault Tolerance)

Hypervisor (ESX, ESXi)

Strategic direction is ESXi

vCenter Server

Management of machines and servers

VMotion and Storage Vmotion

The ability to move running VMs between servers

VMware DRS (Distributed Resource Scheduler)

Allocates resources across VMs on an as-needed and real-time basis

VMware HA (High Availability) and FT (Fault Tolerance)

Automatic failover protection for VMs during server failures

VMware ESX Server includes

"Service Console"

Service Console is...

Extension to the Linux kernel that includes

functionality for script execution, 3rd-party hardware smonitoring and low-level backup

VMware ESXi Server has the same functionality as...

ESX Server

VMware ESXi Server uses a special VM for...

console functionality

VMware ESXi Server can be...

embedded or installable

Embedded

is loaded in firmware - no installation

required

Installable

can run from a USB stick or can network

boot

VMKernel

the underlying O/S, is a scaled down Linux kernel that utilizes an in-memory file system

Multiple APIs allow for...

communication and management at

the VMKernel level

Vmware ESXi Server can...

run diskless.

VMware ESXi have access to...

ESXi interface accomplished via VMware vSphere Client

ESXi servers directly

to manage VMs on that server

HTTP can be used to...

access vCenter but with reduced functionality

The client also provides access to server-specific

configurations such as...

- Storage configuration

- Timekeeping

- Users / Groups

Virtual switches are used to...

allow multiple logical systems to access a single shared NIC

Each Virtual Networking has one or more...

physical Network Interface Cards (NIC)

Each Network Interface Cards has...

an IP Address and a MAC Address

Each NIC connects to...

a virtual switch

Each NIC act like...

physical switches

Each NIC allows connectivity between...

the Physical NIC, Virtual Machines, and the hyper-visor itself

Virtual Switches (vSwitches) are segregated into...

port groups

Each port group can have a separate

802.1Q VLAN

Each VLAN

allows multiple segments to be trunked onto a single connection.

Types of virtual machine port groups:

-Kernel port groups

-Virtual Machine port groups

Kernel port groups are used by... and needed for...

-Used by the hyper-visor itself

- Needed for management, vMotion, SAN storage, etc.

Virtual Machine port groups are used by...

- Used by virtual machines for connectivity

A vSwitch can have

multiple pnics

Teamed to a single switch

for increased bandwidth

Connected to different switches for

fail-over and multi-path

connectivity

A vSwitch may have zero pnics because

Not needed for VM to VM connectivity within the

server

Recommended Network Architecture

Users connect to VMs on a separate network than that used for storage. A third, dedicated network is used for management

Typical configurations when creating a VM

- Name and Inventory location

- Datastore on which to store

- Disk

- #NICS

- VM version (10 requires web interface)

- SCSI controller, node type, i.e. SCSI(0:0)

- ISO images to CD/DVD

In the hard drive, you can dynamically increase...

a virtual disk's size

In the hard drive, you can inflate...

a thin-provisioned disk

In the hard drive, thick provisioned can be migrated...

to thin provisioned

Identity source:

A repository for users and groups that vCenter Single Sign-On can use for

user authentication

What needs to happen to block devices before they can store data?

They need to be partitioned.

Examples of block devices:

- Magnetic hard disk

- Solid State Drives

a.) Flash, SSD

- Optical Drives

a.)CD, DVD, Blu-Ray

- RAID arrays

a.)Hardware

b.) Software

- Storage Area Networks

a.) Fibre Channel, iSCSI, AON

Disks may be numbered starting with what number(s)

0 or 1, depending on the system.

Each platter is referenced by

top and bottom sides or heads

tracks

The data is stored on concentric circles on the

surfaces

cylinder

Identically numbered tracks on all platter

surfaces make up a hollow

sectors

a continuous linear stream of magnetized bits occupying a curved section of a track.

What are the smallest physical storage units on a

disk?

Sectors

Sector management

function of the file system

A block device (single drive or RAID array) represents

a series of blocks and clusters that store data directly

These blocks and clusters must be partitioned into logical sections before...

being used

File systems formats are used...

to hold variable length files

Record/Page/Block systems are used...

hold fixed length data

File system

hierarchy of files and their respective directories.

Partition

collection of consecutive sectors in a volume

Volume

collection of addressable sectors that an operating system or application can use for data storage

True or False: A physical disk contains volumes, which

contain partitions, which are formatted to create

file systems

True

Simple dynamic volumes

Uses free space from a single disk

Spanned dynamic volumes

Uses free space sequentially across multiple disks

Striped dynamic volumes

Uses free space that is interleaved through multiple disks

Mirrored

Uses free space on one disks that is duplicated on a second disk

RAID-5

Uses free space across three or more disks and uses one for parity for fault tolerance

Primary partitions

the default method of creating space in a

volume (basic or dynamic)

Primary file system partition

a partition whose entry is in the MBR and the partition contains a file system or other structured data

Primary extended partition

a partition whose entry is in the MBR, and the partition contains additional partitions

System Partition

• Contains OS files and files needed for booting

• This partition will be bootable and active

Swap Partition

• Can be used to house the swap file

• Reduces / eliminates fragmentation to the swap file