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

Passing metadata and user data to cloud-init

In our examples, we are going to create a file that will essentially be an .iso image and behave like a CD-ROM connected to the booting machine. Cloud-init knows how to handle a situation like this, and will mount the file, extract all the scripts, and run them in a predetermined order, as we already mentioned when we explained how the boot sequence works (check the Understanding cloud-init architecture section earlier in this chapter).

In essence, what we have to do to get the whole thing running is to create an image that will get connected to the cloud template, and that will provide all the data files to the cloud-init scripts inside the template. This is a three-step process:

  1. We have to create the files that hold the configuration information.
  2. We have to create an image that contains the file data in the right place.
  3. We need to associate the image with the template at boot time.

The most complicated part...