Book Image

KVM Virtualization Cookbook

By : Konstantin Ivanov
Book Image

KVM Virtualization Cookbook

By: Konstantin Ivanov

Overview of this book

Virtualization technologies such as KVM allow for better control over the available server resources, by deploying multiple virtual instances on the same physical host, or clusters of compute resources. With KVM it is possible to run various workloads in isolation with the hypervisor layer providing better tenant isolation and higher degree of security. This book will provide a deep dive into deploying KVM virtual machines using qemu and libvirt and will demonstrate practical examples on how to run, scale, monitor, migrate and backup such instances. You will also discover real production ready recipes on deploying KVM instances with OpenStack and how to programatically manage the life cycle of KVM virtual machines using Python. You will learn numerous tips and techniques which will help you deploy & plan the KVM infrastructure. Next, you will be introduced to the working of libvirt libraries and the iPython development environment. Finally, you will be able to tune your Linux kernel for high throughput and better performance. By the end of this book, you will gain all the knowledge needed to be an expert in working with the KVM virtualization infrastructure.
Table of Contents (15 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Configuring NAT forwarding network


When the libvirt daemon starts, it creates a default network defined in the /etc/libvirt/qemu/networks/default.xml configuration file. When a new KVM guest is build without specifying any networking options, it will use the default network to communicate with the host OS and other guests and networks. The default libvirt network is using the Network Address Translation (NAT) method. NAT provides a mapping from one IP address space to another, by modifying the IP address in the header of the IP datagram packet. This is especially useful when the host OS provides one IP address allowing multiple guests on the same host to use that address to establish outbound connections. The virtual machines IP addresses are essentially translated to appear as the host machine's IP address.

The default NAT forwarding network defines and sets up a Linux bridge, for the guests to connect to. In this recipe, we are going to explore the default NAT network and learn about the...