Book Image

Mastering KVM Virtualization - Second Edition

By : Vedran Dakic, Humble Devassy Chirammal, Prasad Mukhedkar, Anil Vettathu
Book Image

Mastering KVM Virtualization - Second Edition

By: Vedran Dakic, Humble Devassy Chirammal, Prasad Mukhedkar, Anil Vettathu

Overview of this book

Kernel-based Virtual Machine (KVM) enables you to virtualize your data center by transforming your Linux operating system into a powerful hypervisor that allows you to manage multiple operating systems with minimal fuss. With this book, you'll gain insights into configuring, troubleshooting, and fixing bugs in KVM virtualization and related software. This second edition of Mastering KVM Virtualization is updated to cover the latest developments in the core KVM components - libvirt and QEMU. Starting with the basics of Linux virtualization, you'll explore VM lifecycle management and migration techniques. You’ll then learn how to use SPICE and VNC protocols while creating VMs and discover best practices for using snapshots. As you progress, you'll integrate third-party tools with Ansible for automation and orchestration. You’ll also learn to scale out and monitor your environments, and will cover oVirt, OpenStack, Eucalyptus, AWS, and ELK stack. Throughout the book, you’ll find out more about tools such as Cloud-Init and Cloudbase-Init. Finally, you'll be taken through the performance tuning and troubleshooting guidelines for KVM-based virtual machines and a hypervisor. By the end of this book, you'll be well-versed with KVM virtualization and the tools and technologies needed to build and manage diverse virtualization environments.
Table of Contents (22 chapters)
Section 1: KVM Virtualization Basics
Section 2: libvirt and ovirt for Virtual Machine Management
Section 3: Automation, Customization, and Orchestration for KVM VMs
Section 4: Scalability, Monitoring, Performance Tuning, and Troubleshooting

Examples on how to use a cloud-config script with cloud-init

First, you need to download the cloud images and resize them in order to make sure that the disk size after everything is installed is large enough to accommodate all the files you plan to put in the machine you created. In these examples, we are going to use two images, one for CentOS, and another for Ubuntu Server. We can see that the CentOS image we are using is 8 GB in size, and we will enlarge it to 10 GB. Note that the actual size on the disk is not going to be 10 GB; we are just allowing the image to grow to this size.

We are going to do the same with the Ubuntu image, after we get it from the internet. Ubuntu also publishes cloud versions of their distribution daily, for all supported versions. The main difference is that Ubuntu creates images that are designed to be 2.2 GB when full. We downloaded an image from; let's now get some information about it: