Novell LINUX ENTERPRISE SERVER 11 - VIRTUALIZATION User manual

SUSE Linux Enterprise
Server
www.novell.com11
May27,2009 Virtualization with Xen

Virtualization with Xen
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Contents
About This Manual vii
1Introduction to Xen Virtualization 1
1.1 BasicComponents......................... 1
1.2 Understanding Virtualization Modes . . . . . . . . . . . . . . . . . 2
1.3 Xen Virtualization Architecture . . . . . . . . . . . . . . . . . . . . 3
1.4 The Virtual Machine Host . . . . . . . . . . . . . . . . . . . . . . 4
2Setting Up a Virtual Machine Host 7
2.1 Best Practices and Suggestions . . . . . . . . . . . . . . . . . . . . 8
2.2 Managing Domain 0 Memory . . . . . . . . . . . . . . . . . . . . 9
2.3 Network Card in Fully Virtualized Guests . . . . . . . . . . . . . . . 10
2.4 Starting the Virtual Machine Host . . . . . . . . . . . . . . . . . . 12
2.5 PCIPass-Through......................... 13
3Setting Up Virtual Machines 17
3.1 Creating a Virtual Machine . . . . . . . . . . . . . . . . . . . . . 18
3.2 Installing an Operating System . . . . . . . . . . . . . . . . . . . 19
3.3 Including Add-On Products in the Installation . . . . . . . . . . . . . 24
3.4 Using the Command Line to Create Virtual Machines . . . . . . . . . . 25
3.5 Deleting Virtual Machines . . . . . . . . . . . . . . . . . . . . . 25
3.6 Using an Existing SUSE Linux Enterprise Server Virtual Machine . . . . . 25
3.7 Troubleshooting ......................... 26
4Managing a Virtualization Environment 29
4.1 Virtual Machine Manager . . . . . . . . . . . . . . . . . . . . . 30

4.2 Controlling the Host by Modifying xend Settings . . . . . . . . . . . . 32
4.3 Conguring a Virtual Machine by Modifying its xend Settings . . . . . . 33
4.4 ThexmCommand........................ 34
4.5 Automatic Starting of Domains . . . . . . . . . . . . . . . . . . . 36
4.6 Migrating Xen VM Guest Systems . . . . . . . . . . . . . . . . . . 36
5Virtual Networking 39
5.1 VirtualBridges.......................... 40
5.2 Network Devices for Guest Systems . . . . . . . . . . . . . . . . . 40
5.3 Special Congurations . . . . . . . . . . . . . . . . . . . . . . . 42
6Virtualization: Conguration Options and Settings 47
6.1 Updating SLE 10 VM Host Server Systems to SLE 11 . . . . . . . . . . 47
6.2 VirtualCDReaders........................ 49
6.3 Remote Access Methods . . . . . . . . . . . . . . . . . . . . . . 53
6.4 VNCViewer........................... 54
6.5 The Boot Loader Program . . . . . . . . . . . . . . . . . . . . . 57
6.6 Virtual Machine Initial Startup Files . . . . . . . . . . . . . . . . . 60
6.7 Sparse Image Files and Disk Space . . . . . . . . . . . . . . . . . . 62
6.8 VirtualKeyboards......................... 63
6.9 Mapping Physical Storage to Virtual Disks . . . . . . . . . . . . . . . 65
6.10 VirtualDisks........................... 67
6.11 Migrating Virtual Machines . . . . . . . . . . . . . . . . . . . . . 67
6.12 Passing Key Combinations to Virtual Machines . . . . . . . . . . . . . 68
6.13 xm block-list Device Numbers . . . . . . . . . . . . . . . . . . . . 69
6.14 File-Backed Virtual Disks and Loopback Devices . . . . . . . . . . . . 69
6.15 Saving Virtual Machines . . . . . . . . . . . . . . . . . . . . . . 70
6.16 Restoring Virtual Machines . . . . . . . . . . . . . . . . . . . . . 71
6.17 Virtual Machine States . . . . . . . . . . . . . . . . . . . . . . . 72
7Xen Guest Systems 75
7.1 NetWare Virtual Machines . . . . . . . . . . . . . . . . . . . . . 75
7.2 OES Linux Virtual Machines . . . . . . . . . . . . . . . . . . . . . 75
7.3 Red Hat Linux Virtual Machines . . . . . . . . . . . . . . . . . . . 75
7.4 SUSE Linux Virtual Machines . . . . . . . . . . . . . . . . . . . . 77
7.5 Windows Virtual Machines . . . . . . . . . . . . . . . . . . . . . 84
8Virtual Machine Drivers 85
8.1 Buying a Support Subscription . . . . . . . . . . . . . . . . . . . 86
8.2 Loading the Driver Pack . . . . . . . . . . . . . . . . . . . . . . 87
8.3 SUSE Drivers for Red Hat Enterprise Linux 4 on Xen . . . . . . . . . . 87

8.4 SUSE Drivers for Red Hat Enterprise Linux 5 on Xen . . . . . . . . . . 91
8.5 SUSE Drivers for Windows on Xen . . . . . . . . . . . . . . . . . . 95
8.6 SUSE Drivers for SUSE Linux Enterprise Server on Xen . . . . . . . . . 103
ASXP Conguration Options 105

About This Manual
This manual offers an introduction to virtualization technology of your SUSE Linux
Enterprise Server. It features an overview of the various elds of application and instal-
lation types of each of the platforms supported by SUSE Linux Enterprise Server as
well as a short description of the installation procedure.
Many chapters in this manual contain links to additional documentation resources. This
includes additional documentation that is available on the system as well as documen-
tation available on the Internet.
For an overview of the documentation available for your product and the latest docu-
mentation updates, refer to http://www.novell.com/documentation.
Quality service is also available. Experts can answer questions about installation or
conguration, make reliable security updates available, and support development
projects.
Documentation regarding the Open Enterprise Server 2 is found at http://www
.novell.com/documentation/oes2/index.html.
1 Available Documentation
We provide HTML and PDF versions of our books in different languages. The following
manuals for users and administrators are available on this product:
Deployment Guide (↑Deployment Guide)
Shows how to install single or multiple systems and how to exploit the product
inherent capabilities for a deployment infrastructure. Choose from various approach-
es, ranging from a local installation or a network installation server to a mass de-
ployment using a remote-controlled, highly-customized, and automated installation
technique.
Administration Guide (↑Administration Guide)
Covers system administration tasks like maintaining, monitoring and customizing
an initially installed system.

Security Guide (↑Security Guide)
Introduces basic concepts of system security, covering both local and network se-
curity aspects. Shows how to make use of the product inherent security software
like Novell AppArmor (which lets you specify per program which les the program
may read, write, and execute) or the auditing system that reliably collects informa-
tion about any security-relevant events.
System Analysis and Tuning Guide (↑System Analysis and Tuning Guide)
An administrator's guide for problem detection, resolution and optimization. Find
how to inspect and optimize your system by means of monitoring tools and how
to efciently manage resources. Also contains an overview of common problems
and solutions and of additional help and documentation resources.
Virtualization with Xen (page 1)
Offers an introduction to virtualization technology of your product. It features an
overview of the various elds of application and installation types of each of the
platforms supported by SUSE Linux Enterprise Server as well as a short description
of the installation procedure.
Storage Administration Guide
Provides information about how to manage storage devices on a SUSE Linux En-
terprise Server.
In addition to the comprehensive manuals, several quick start guides are available:
Installation Quick Start (↑Installation Quick Start)
Lists the system requirements and guides you step-by-step through the installation
of SUSE Linux Enterprise Server from DVD, or from an ISO image.
Linux Audit Quick Start
Gives a short overview how to enable and congure the auditing system and how
to execute key tasks such as setting up audit rules, generating reports, and analyzing
the log les.
Novell AppArmor Quick Start
Helps you understand the main concepts behind Novell® AppArmor.
Find HTML versions of most SUSE Linux Enterprise Server manuals in your installed
system under /usr/share/doc/manual or in the help centers of your desktop.
Find the latest documentation updates at http://www.novell.com/
viii Virtualization with Xen

documentation where you can download PDF or HTML versions of the manuals
for your product.
2 Feedback
Several feedback channels are available:
• To report bugs for a product component or to submit enhancement requests, please
use https://bugzilla.novell.com/. If you are new to Bugzilla, you
might nd the Bug Writing FAQs helpful, available from the Novell Bugzilla home
page.
• We want to hear your comments and suggestions about this manual and the other
documentation included with this product. Please use the User Comments feature
at the bottom of each page of the online documentation and enter your comments
there.
3 Documentation Conventions
The following typographical conventions are used in this manual:
•/etc/passwd: directory names and lenames
•placeholder: replace placeholder with the actual value
•PATH: the environment variable PATH
•ls,--help: commands, options, and parameters
•user: users or groups
•Alt,Alt +F1: a key to press or a key combination; keys are shown in uppercase as
on a keyboard
•File,File >Save As: menu items, buttons
•►amd64 em64t: This paragraph is only relevant for the specied architectures.
The arrows mark the beginning and the end of the text block. ◄
About This Manual ix

•Dancing Penguins (Chapter Penguins, ↑Another Manual): This is a reference to a
chapter in another manual.
xVirtualization with Xen

1
Introduction to Xen
Virtualization
Virtualization of operating systems is used in many different computing areas. It nds
its applications in server consolidation, energy saving efforts, or the ability to run older
software on new hardware, for example. This chapter introduces and explains the
components and technologies you need to understand to set up and manage a Xen-based
virtualization environment.
1.1 Basic Components
The basic components of a Xen-based virtualization environment are the Xen hypervisor,
the Domain0, any number of other VM Guests, and the tools, commands, and congu-
ration les that let you manage virtualization. Collectively, the physical computer run-
ning all these components is referred to as a VM Host Server because together these
components form a platform for hosting virtual machines.
The Xen Hypervisor
The Xen hypervisor, sometimes referred to generically as a virtual machine monitor,
is an open-source software program that coordinates the low-level interaction be-
tween virtual machines and physical hardware.
The Domain0
The virtual machine host environment, also referred to as Domain0 or controlling
domain, is comprised of several components, such as:
Introduction to Xen Virtualization 1

• The SUSE Linux operating system, which gives the administrator a graphical
and command line environment to manage the virtual machine host components
and its virtual machines.
NOTE
The term “Domain0” refers to a special domain that provides the manage-
ment environment. This may be run either in graphical or in command
line mode.
• The xend daemon (xend), which stores conguration information about each
virtual machine and controls how virtual machines are created and managed.
• A modied version of QEMU, which is an open-source software program that
emulates a full computer system, including a processor and various peripherals.
It provides the ability to host operating systems in full virtualization mode.
Xen-Based Virtual Machines
A Xen-based virtual machine, also referred to as a VM Guest or DomU consists
of the following components:
• At least one virtual disk that contains a bootable operating system. The virtual
disk can be based on a le, partition, volume, or other type of block device.
• Virtual machine conguration information, which can be modied by exporting
a text-based conguration le from xend or through Virtual Machine Manager.
Management Tools, Commands, and Conguration Files
There is a combination of GUI tools, commands, and conguration les to help
you manage and customize your virtualization environment.
1.2 Understanding Virtualization
Modes
Guest operating systems are hosted on virtual machines in either full virtualization
mode or paravirtual mode. Each virtualization mode has advantages and disadvantages.
2Virtualization with Xen

• Full virtualization mode lets virtual machines run unmodied operating systems,
such as Windows* Server 2003 and Windows XP, but requires the computer running
as the VM Host Server to support hardware-assisted virtualization technology, such
as AMD* Virtualization or Intel* Virtualization Technology.
Some guest operating systems hosted in full virtualization mode, can be congured
to run the Novell* Virtual Machine Drivers instead of drivers originating from the
operating system. Running virtual machine drivers improves performance dramat-
ically on guest operating systems, such as Windows XP and Windows Server 2003.
For more information, see Chapter 8, Virtual Machine Drivers (page 85).
• Paravirtual mode does not require the host computer to support hardware-assisted
virtualization technology, but does require the guest operating system to be modied
for the virtualization environment. Typically, operating systems running in paravir-
tual mode enjoy better performance than those requiring full virtualization mode.
Operating systems currently modied to run in paravirtual mode are referred to as
paravirtualized operating systems and include SUSE Linux Enterprise Server 11
and NetWare® 6.5 SP8.
1.3 Xen Virtualization Architecture
The following graphic depicts a virtual machine host with four virtual machines. The
Xen hypervisor is shown as running directly on the physical hardware platform. Note,
that the controlling domain is also just a virtual machine, although it has several addi-
tional management tasks compared to all other virtual machines.
Introduction to Xen Virtualization 3

Figure 1.1 Virtualization Architecture
On the left, the virtual machine host’s Domain0 is shown running the SUSE Linux op-
erating system. The two virtual machines shown in the middle are running paravirtualized
operating systems. The virtual machine on the right shows a fully virtual machine run-
ning an unmodied operating system, such as Windows Server 2003 or Windows XP.
1.4 The Virtual Machine Host
After you install the virtualization components and reboot the computer, the GRUB
boot loader menu displays a Xen menu option. Selecting the Xen menu option loads
the Xen hypervisor and starts the Domain0 running the SUSE Linux operating system.
Running on Domain0, the SUSE Linux operating system displays the installed text
console or desktop environment, such as GNOME or KDE. The terminals of VM Guest
systems are displayed in their own window inside the controlling Domain0 when opened.
4Virtualization with Xen

Figure 1.2 Desktop Showing Virtual Machine Manager and Virtual Machines
Introduction to Xen Virtualization 5

2
Setting Up a Virtual Machine
Host
This section documents how to set up and use SUSE Linux Enterprise 11 as a virtual
machine host.
In most cases, the hardware requirements for the Domain0 are the same as those for
the SUSE Linux Enterprise Server operating system, but additional CPU, disk, memory,
and network resources should be added to accommodate the resource demands of all
planned VM Guest systems.
TIP
Remember that VM Guest systems, just like physical machines, perform better
when they run on faster processors and have access to more system memory.
The following table lists the minimum hardware requirements for running a typical
virtualized environment. Additional requirements have to be added for the number and
type of the respective guest systems.
Table 2.1 Hardware Requirements
Minimum RequirementsSystem Compo-
nent
Computer with Pentium II or AMD K7 450 MHz processorComputer
512 MB of RAM for the hostMemory
Setting Up a Virtual Machine Host 7

Minimum RequirementsSystem Compo-
nent
7 GB of available disk space for the host.Free Disk Space
DVD-ROM DriveOptical Drive
20 GBHard Drive
Ethernet 100 MbpsNetwork Board
IP Address • One IP address on a subnet for the host.
• One IP address on a subnet for each VM Guest.
Xen virtualization technology is available in SUSE Linux Enterprise Server products
based on code path 10 and later. Code path 10 products include Open Enterprise Server
2 Linux, SUSE Linux Enterprise Server 10, SUSE Linux Enterprise Desktop 10, and
openSUSE 10.x.
The virtual machine host requires a number of software packages and their dependencies
to be installed. To install all necessary packages, run YaST Software Management, select
the lter Patterns and choose Xen Virtual Machine Host Server for installation. The
installation can also be performed with YaST using the module Virtualization >Install
Hypervisor and Tools.
After the Xen software is installed, restart the computer.
Updates are available through your update channel. To be sure to have the latest updates
installed, run YaST Online Update after the installation has nished.
2.1 Best Practices and Suggestions
When installing and conguring the SUSE Linux Enterprise operating system on the
host, be aware of the following best practices and suggestions:
8Virtualization with Xen

•If the host should always run as Xen host, run YaST System >Boot Loader and
activate the Xen boot entry as default boot section.
•In YaST, click System > Boot Loader.
•Change the default boot to the Xen label, then click Set as Default.
•Click Finish.
• Close Virtual Machine Manager if you are not actively using it and restart it when
needed. Closing Virtual Machine Manager does not affect the state of virtual ma-
chines.
•For best performance, only the applications and processes required for virtualization
should be installed on the virtual machine host.
• When using both, iSCSI and OCFS2 to host Xen images, the latency required for
OCFS2 default timeouts in SP2 may not be met. To recongure this timeout, run
/etc/init.d/o2cb configure or edit O2CB_HEARTBEAT_THRESHOLD
in the system conguration.
2.2 Managing Domain 0 Memory
When the host is set up, a percentage of system memory is reserved for the hypervisor,
and all remaining memory is automatically allocated to Domain0.
A better solution is to set a minimum and maximum amount of memory for domain 0,
so the memory can be allocated appropriately to the hypervisor. An adequate maximum
amount would be 20 percent of the total system memory up to 2 GB. An appropriate
minimum amount would be 512 MB.
2.2.1 Setting a Maximum Amount of
Memory
1Determine the amount of memory to set for domain 0.
2At Domain0, type xm list to view the currently allocated memory.
Setting Up a Virtual Machine Host 9

3Run YaST >Boot Loader.
4Select the Xen section.
5In Additional Xen Hypervisor Parameters, add dom0_mem=mem_amount
where mem_amount is the maximum amount of memory to allocate to Domain0.
Add K,M, or G, to specify the size, for example, dom0_mem=768M.
6Restart the computer to apply the changes.
2.2.2 Setting a Minimum Amount of Memory
To set a minimum amount of memory for Domain0, edit the dom0-min-mem param-
eter in the /etc/xen/xend-config.sxp le and restart xend. For more informa-
tion, see Section 4.2, “Controlling the Host by Modifying xend Settings” (page 32).
2.3 Network Card in Fully Virtualized
Guests
In a fully virtualized guest, the default network card is an emulated Realtek network
card. However, it also possible to use the split network driver to run the communication
between Domain0 and a VM Guest. By default, both interfaces are presented to the
VM Guest, because the drivers of some operating systems require both to be present.
When using SUSE Linux Enterprise, only the paravirtualized network cards are available
for the VM Guest by default. The following network options are available:
emulated
To use a “emulated” network interface like an emulated Realtek card, specify
(type ioemu) in the vif device section of the xend conguration. An example
conguration would look like:
(device
(vif
(bridge br0)
(uuid e2b8f872-88c7-0a4a-b965-82f7d5bdd31e)
(devid 0)
10 Virtualization with Xen