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

Memory tuning for KVM guests


When it comes to memory tuning of KVM guests there are few options available, depending on the workload of the virtual machine. One such option is Linux HugePages.

Most Linux hosts by default address memory in 4 KB segments, named pages. However, the kernel is capable of using larger page sizes. Using HugePages (pages bigger than 4 KB) may improve performance by increasing the CPU cache hits against the transaction Lookaside Buffer (TLB). The TLB is a memory cache that stores recent translations of virtual memory to physical addresses for quick retrieval.

In this recipe, we are going to enable and set HugePages on the hypervisor and the KVM guest, then examine the tuning options that the virsh command provides.

Getting ready

For this recipe, we are going to need the following:

  • An Ubuntu host, with libvirt and QEMU installed and configured
  • A running KVM virtual machine

How to do it...

To enable and set HugePages on the hypervisor and the KVM guest and use the virsh command...