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the amount of memory allocated to the guest session. The default memory allocated to

the system frequently is fine for a basic system configuration; however, with the addition

of applications to the guest session, there might be a need to increase the memory. As

long as the host server system has enough memory to allocate additional memory to the

guest session, adding memory to a guest session is a very simple task.

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To add memory to the guest session, do the following:

1. From the Server Manager console or from the Hyper-V Manager MMC snap-in, click

to select the guest session for which you want to change the allocated memory.

2. Right-click the guest session name, and choose Settings.

3. Click on Memory and enter in the amount of RAM you want allocated for this guest

session (in megabytes).

4. Click OK when you are finished.

NOTE

You cannot change the allocated RAM on a running virtual guest session. The guest

session must be shut down first, memory reallocated to the image, and then the guest

image booted for the new memory allocation to take effect.

Changing Network Settings for the Guest Session

Another common configuration change made to a guest session is to change the network

setting for the guest session. An administrator of a virtual server might choose to have

each guest session connected directly to the network backbone with an external network,

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just as if the guest session had a network adapter connected to the backbone, or the

network administrator might choose to set up an isolated (internal or private) network

just for the guest sessions. The configuration of the internal, private, and external network

segments that the administrator can configure the guest sessions to connect to is covered

earlier in this chapter in the section “Virtual Network Manager.”

The common configuration methods of the virtual network configurations can be broken

down into two groups, as follows:

.
Direct addressing—
The guest sessions can connect directly to the backbone of the

network to which the virtual server host system is attached. In this instance, an

administrator would configure an external connection in the Virtual Network

Manager and have an IP address on that external segment.

.
Isolated network—
If the administrator wants to keep the guest sessions isolated off

of the network backbone, the administrator can set up either an internal or private

connection in the Virtual Network Manager and the guest sessions would have an IP

address of a segment common to the other guest sessions on the host system. In this

case, the virtual server acts as a network switch connecting the guest sessions togeth-

er.

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NOTE

To connect the internal network segment with the external network segment, a guest

session can be configured as a router or gateway between the internal network and

external network. This router system would have two virtual network adapters, one for

each network.

To change the connected network used by a guest session adapter, do the following:

1. From the Server Manager console or from the Hyper-V Manager MMC snap-in, click

to select the guest session for which you want to change the network configuration.

2. Right-click the guest session name, and choose Settings.

3. Click on the network adapter that requires reconfiguration. From the list in the

Network field, select the desired network.

4. Click OK when you are finished.

Mounting a Physical CD/DVD Image or Mounting a CD/DVD Image File

When installing software on a guest session of a virtual server system, the administrator

would either insert a CD or DVD into the drive of the physical server and access the disc

from the guest session, or mount an ISO image file of the disc media.

To access a physical CD or DVD disc or to mount an image of a CD or DVD, do the

following:

1. From the Server Manager console or from the Hyper-V Manager MMC snap-in, click

to select the guest session for which you want to provide access to the CD or DVD.

Launching a Hyper-V Guest Session

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2. Right-click the guest session name, and choose Settings.

3. Click on DVD Drive and choose Physical CD/DVD Drive if you want to mount a disc

in the physical drive of the host system, or click on Image File and browse for the

ISO image file you want to mount as a disc image.

4. Click OK when you are finished.

Other Settings to Modify for a Guest Session Configuration

There are other settings that can be changed for a guest session. These options can be

modified by going into the Settings option of the guest session and making changes.

These other settings include the following:

.
BIOS—
This setting allows for the selection of boot order on the guest machine to

boot in an order that can include floppy, CD, IDE (disk), or network boot.

.
Processor—
Hyper-V provides the ability to allocate core processors to the guest

image, so a guest image can have up to four core processors allocated for each

session. Additionally, resource control can be weighted between guest sessions by

allocating system resource priority to key guest server sessions versus other guest

sessions.

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NOTE

Windows Server 2008 R2 provides a processor compatibility check box to limit proces-

sor functionality for virtual machines that will be Live Migrated between dissimilar

hosts. Live Migration is discussed later in this chapter.

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.
IDE Controller—
The guest session initially has a single virtual hard drive associated

with it. Additional virtual hard drives can be added to a virtual guest session.

.
SCSI Controller—
A virtual SCSI controller can be associated with a virtual guest

session as well providing different drive configuration options for the different drive

configurations.

.
COM Ports—
Virtual communication ports such as COM1 or COM2 can be associat-

ed with specific named pipes for input and output of information.

Launching a Hyper-V Guest Session

After a Hyper-V guest session has been created, and the settings have been properly modi-

fied to meet the expected needs of the organization, the virtual guest session can now be

launched and run. Decisions need to be made whether you want the guest session to auto-

matically launch as soon as the host server is booted, or whether you want to manually

launch a guest session. Additionally, a decision needs to be made on the sequence in

which guest sessions should be launched so that systems that are prerequisites to other

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sessions come up first. As an example, you’d want a global catalog server session and

DHCP server session to come up before an application server that logs on and authenti-

cates to Active Directory comes online and needs to authenticate to Active Directory

before the server service begins.

Automatically Launching a Guest Session

One option for launching and loading guest sessions is to have the guest session boot right

after the physical host server completes the boot cycle. This is typically the preferred

option if a guest session is core to the network infrastructure of a network (such as a

domain controller or host server system) so that in the event of a physical server reboot,

the virtual guest sessions boot up automatically as well. It would not be convenient to have

to manually boot each virtual server session every time the physical server is rebooted.

The option for setting the startup option for a virtual session is in the configuration

settings for each guest session.

To change the startup action, do the following:

1. From the Server Manager console or from the Hyper-V Manager MMC snap-in,

right-click the virtual machine for which you want to change the setup option, and

select Settings.

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2. In the Management section of the settings, click Automatic Start Action.

3. You are provided with three options, as shown in Figure 37.7, of what to do with

this virtual guest session upon startup of the physical host server. Either click

Nothing (which would require a manual boot of the guest session), click

Automatically Start If It Was Running When the Service Stopped, or click Always

Start This Virtual Machine Automatically. To set the virtual session to automatically

start after the physical server comes up, choose the Always Start This Virtual

Machine Automatically option.

4. Also on this setting is the ability to have an automatic start delay. This enables you

to sequence the startup of virtual machines by having some VMs take longer to

automatically start than others. Click OK to save these settings.

Manually Launching a Guest Session

Another option for guest session startup is to not have a guest session automatically start

after a physical server boots up. This is typically the preferred option if a guest session will

be part of a demonstration or test server where the administrator of the system wants to

control which guest sessions are automatically launched, and which sessions need to be

manually launched. It would not be convenient to have a series of demo or test sessions

automatically boot up every time the system is booted. The administrator of the system

would typically want to choose to start these guest sessions.

Launching a Hyper-V Guest Session

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FIGURE 37.7

Automatic start actions.

To set the startup action to manually launch a guest session, do the following:

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1. From the Server Manager console or from the Hyper-V Manager MMC snap-in,

right-click the virtual machine for which you want to change the setup option, and

select Settings.

2. In the Management section of the settings, click Automatic Start Action.

3. When provided the three options of what to do with this virtual guest session upon

startup of the physical server, either click Nothing (which would require a manual

boot of the guest session), click Automatically Start If It Was Running when the

Service Stopped, or click Always Start This Virtual Machine Automatically. Choose

the Nothing option, and the session will need to be manually started.

Save State of a Guest Session

In Windows Server 2008 R2 Hyper-V, there are two concepts for saving guest images: being

snapshots and being a saved state. At any time, an administrator can right-click a guest

session and choose Save. This Save function is similar to a Hibernate mode on a desktop

client system. It saves the image state into a file with the option of bringing the saved

state image file back to the state the image was in prior to being saved.

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Using Snapshots of Guest Operating System Sessions

A highly versatile function in Windows Server 2008 R2 Hyper-V is the option to create a

snapshot of a guest session. A snapshot in Windows Hyper-V uses Microsoft Volume

Shadow Copy Service (VSS) technology that captures an image of a file on a server—in this

case, the file is the VHD image of the virtual server itself. At any point in time in the

future, the snapshot can be used for recovery.

Snapshots for Image Rollback

One common use of a guest image snapshot is to roll back an image to a previous state.

This is frequently done with guest images used for demonstration purposes, or test labs

where a scenario is tested to see the results and compared with identical tests of other

scenarios, or for the purpose of preparing for a software upgrade or migration.

In the case of a guest image used for demonstration purposes, a user might run through a

demo of a software program where they add information, delete information, make soft-

ware changes, or otherwise modify information in the software on the guest image. Rather

than having to go back and delete the changes, or rebuilding the image from scratch to do

the demo again, with a snapshot, the user can simply roll the image back to the snapshot

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that was available before the changes were made to the image.