User Mode Linux®

With User Mode Linux you can create virtual Linux machines within a Linux computer and use them to safely test and debug applications, network services, and even kernels. You can try out new distributions, experiment with buggy software, and even test security. Now, for the first time, the creator and maintainer of User Mode Linux shows how to put it to work hands-on. Jeff Dike covers everything from getting started through running enterprise-class User Mode Linux servers. You'll find authoritative advice on bootup, compilation, administration, specialized configurations, and much more.

Coverage includes

• What User Mode Linux is, how it works, and its uses in Linux networks
• Key applications, including server consolidation, development, and disaster recovery
• Booting and exploration: logins, consoles, swap space, partitioned disks, and more
• Copy-On-Write (COW): UML's efficient approach to storing filesystem changes
• In-depth discussion of User Mode Linux networking and security
• Centrally managing User Mode Linux instances, and controlling their hardware resources
• Implementing clusters and other specialized configurations
• Setting up User Mode Linux servers, step-by-step: small-scale and large-scale examples
• The future of virtualization and User Mode Linux

Whether you're a netadmin, sysadmin, teacher, student, or programmer, User Mode Linux®--the technology and this book--is indispensable.

Online Sample Chapter

Introduction to User Mode Linux

Sample Chapter(s)

Download the Sample Chapter related to this title.

Index

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Table of Contents

Preface     ix
Acknowledgments     xi
About the Author     xiiiChapter 1: Introduction     1

What Is UML?     1
Comparison with Other Virtualization Technologies     2
Why Virtual Machines?     3
A Bit of History     4
What Is UML Used For?     8
The Future     14

Chapter 2: A Quick Look at UML     17

Booting UML for the First Time     20
Booting UML Successfully     24
Looking at a UML from the Inside and Outside     29
Conclusion     37

Chapter 3: Exploring UML     39

Logging In as a Normal User     39
Consoles and Serial Lines     40
Adding Swap Space     47
Partitioned Disks     49
UML Disks as Raw Data     53
Networking     54
Shutting Down     59

Chapter 4: A Second UML Instance     61

COW Files     61
Networking the UML Instances     71
A Virtual Serial Line     79

Chapter 5: Playing with a UML Instance     83

Use and Abuse of UML Block Devices     83
Networking and the Host     87

Chapter 6: UML Filesystem Management     101

Mounting Host Directories within a UML     101
Host Access to UML Filesystems     114
Making Backups     116
Extending Filesystems     117
When to Use What     118

Chapter 7: UML Networking in Depth     121

Manually Setting Up Networking     121
The UML Networking Transports     142
An Extended Example     155

Chapter 8: Managing UML Instances from the Host     167

The Management Console     167
Controlling a UML Instance with Signals     188

Chapter 9: Host Setup for a Small UML Server     191

Host Kernel Version     192
UML Execution Modes     194
Managing Long-Lived UML Instances     203
Networking     206
UML Physical Memory     206
Host Memory Consumption     208
umid Directories     209
Overall Recommendations     209

Chapter 10: Large UML Server Management     211

Security     212
Jailing UML Instances     216
Providing Console Access Securely     223
skas3 versus skas0     225
Future Enhancements     226
Final Points     232

Chapter 11: Compiling UML from Source     233

Downloading UML Source     234
Configuration     235
Compilation     249

Chapter 12: Specialized UML Configurations     251

Large Numbers of Devices     252
Clusters     265
UML as a Decision-Making Tool for Hardware     273

Chapter 13: The Future of UML     275

The externfs Filesystem     277
Virtual Processes     282
Captive UML     283
Virtualized Subsystems     295
Conclusion     298

Appendix A: UML Command-Line Options     301

Device and Hardware Specifications     301
Debugging Options     303
Management Options     304
Informational Options     305

Appendix B: UML Utilities Reference     307

humfsify     307
uml_moo     308
uml_mconsole     308
tunctl     310
uml_switch     311
Internal Utilities     312

Index     313