Chapter 3. Setting Up Virtual Machines / 3.2. Installing an Operating System
	Chapter 3. Setting Up Virtual Machines		3.3. Including Add-On Products in the Installation

Installing an Operating System

You can choose to run an installation program or choose a disk or disk image that already has an installed and bootable operating system.

Figure 3.1. Installing an Operating System

If you choose to run an installation program, you are presented with a list of operating systems. Select the one you want to install.

The Summary page shows you a summary of the virtual machine you are creating. You can click on any of the headings to edit the information. As you edit the information in the Summary, consult Chapter 6, Xen Guest Systems for instructions specific to the operating system you are installing.

Figure 3.2. Summary

Information about the following operating systems is included:

OES NetWare Virtual Machines, see Section 6.1, “NetWare Virtual Machines”.
OES Linux Virtual Machines, see Section 6.2, “OES Linux Virtual Machines”.
SUSE Linux Virtual Machines, see Section 6.3, “SUSE Linux Virtual Machines”.
Windows Virtual Machines, see Section 6.4, “Windows Virtual Machines”.

When running through the creation of a VM Guest, the following steps have to be accomplished:

Select if the VM Guest should run as full or paravirtualized guest.
If your computer supports hardware-assisted virtualization, you can create a virtual machine that runs in fully virtual mode. If you are installing an operating system that is modified for virtualization, you can create a virtual machine that runs in paravirtual mode. For more information about virtualization modes, see Section 1.2, “Understanding Virtualization Modes”.
Each virtual machine must have a unique name. The name entered on this page is used to create and name the virtual machine’s configuration file. The configuration file contains parameters that define the virtual machine and is saved to the /etc/xen/vm/ directory.
The Hardware page allows you to specify the amount of memory and number of virtual processors for your virtual machine.
Initial Memory
The amount of memory initially allocated to the virtual machine (specified in megabytes).
Maximum Memory
The largest amount of memory the virtual machine will ever need.
Virtual Processors
If desired, you can specify that the virtual machine has more virtual CPUs than the number of physical CPUs. You can specify up to 32 virtual CPUs: however, for best performance, the number of virtual processors should be less than or equal to the number of physical processors.
Select the graphics mode to use:
No Graphics Support
The virtual machine operates like a server without a monitor. You can access the operating system through operating system supported services, such as SSH or VNC.
Paravirtualized Graphics Adapter
Requires that an appropriate graphics driver is installed in the operating system.
A virtual machine must have at least one virtual disk. Virtual disks can be:
- File backed, which means that the virtual disk is a single image file on a larger physical disk.
- A sparse image file, which means that the virtual disk is a single image file, but the space is not preallocated.
- Configured from a block device, such as an entire disk, partition, or volume.
For best performance, create each virtual disk from an entire disk or a partition. For the next best performance, create an image file but do not create it as a sparse image file. A virtual disk based on a sparse image file delivers the most disk-space flexibility but slows installation and disk access speeds.
By default, a single, file-backed virtual disk is created as a sparse image file in /var/lib/xen/images/vm_name where vm_name is the name of the virtual machine. You can change this configuration to meet your specific requirements.
If you want to install from DVD or CD-Rom, add the drive to the list of available hard disks. To learn about device names of the available optical drives, run hwinfo --cdrom and search for the line starting with Device File:. Add this device file to the available hard disks of the VM Guest.

By default, a single virtual network card is created for the virtual machine. It has a randomly generated MAC address that you can change to fit your desired configuration. The virtual network card will be attached to a default bridge configured in the host. You can also create additional virtual network cards in the Network Adapters page of vm-install.

	Using Arbitrary Bridge Names
If installing a fully virtualized guest and you are using a bridge name that is different than the default names, explicitly specify the bridge by selecting the bridge name from the Source menu on the Virtual Network Adapter page. Paravirtual guests by definition are aware they are running on a virtualization platform and therefore, do not need to have the bridge explicitly specified, thus leaving Source as Default will suffice.

Using Arbitrary Bridge Names

If installing a fully virtualized guest and you are using a bridge name that is different than the default names, explicitly specify the bridge by selecting the bridge name from the Source menu on the Virtual Network Adapter page. Paravirtual guests by definition are aware they are running on a virtualization platform and therefore, do not need to have the bridge explicitly specified, thus leaving Source as Default will suffice.

The operating system can be installed from a CD/DVD device or an ISO image file. In addition, if you are installing a SUSE Linux operating system, you can install the operating system from a network installation source.

If you are installing a paravirtual machine's operating system from CD, you should remove the virtual CD reader from the virtual machine after completing the installation, because the virtual machine assumes that the original CD is still in the CD reader, even if it is ejected. If it is ejected, the virtual machine cannot access the CD (or any other newly inserted CD) and receives I/O errors.

	Changing CD-Roms
On paravirtual guests, it is currently not possible to go on with the installation of a system after changing the CD-Rom. Instead, you should use a DVD or a network based installation. For a workaround to this problem, see Section 5.1.1, “Virtual CD Readers on Paravirtual Machines”.

If the installation program is capable of recognizing an installation profile, response file, or script, you can automate the installation settings by specifying the location of the profile, response file, or script you want to use. For example, SUSE Linux uses an AutoYaST profile, NetWare uses a NetWare Response File, and Red Hat uses a Kickstart file to move through the installation screens with no interaction.

You can also pass instructions to the kernel at install time by entering parameters for the Additional Arguments field. These arguments may either be kernel options, or options for linuxrc. More information about linuxrc can be found at http://www.novell.com/documentation/sles10/sles_admin/data/sec_deployment_remoteinst_bootinst.html

If all the information on the Summary screen is correct, click OK to create the virtual machine. A TightVNC screen appears and at this point you begin the installation of your OS. From this point on, follow the regular installation instructions for installing your OS. More information for any instructions that might be different for installing your OS in a virtualized environment may be found in Chapter 6, Xen Guest Systems.