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

Introduction


Migrating KVM instances is the process of sending the state of the guest virtual machine's memory, CPU, and virtualized devices attached to it, to a different server. Migrating KVM instances is a somewhat complicated process, depending on what backend storage the VM is using (that is, directory, image file, iSCSI volume, shared storage, or storage pools), the network infrastructure, and the number of block devices attached to the guest. There are following the two types of migrations as far as libvirt is concerned:

  • Offline migration involves downtime for the instance. It works by first suspending the guest VM, then copying an image of the guest memory to the destination hypervisor. The KVM machine is then resumed on the target host. If the filesystem of the VM is not on a shared storage, then it needs to be moved to the target server as well.
  • Live migration works by moving the instance in its current state with no perceived downtime, preserving the memory and CPU register states...