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)
1
Section 1: KVM Virtualization Basics
4
Section 2: libvirt and ovirt for Virtual Machine Management
11
Section 3: Automation, Customization, and Orchestration for KVM VMs
15
Section 4: Scalability, Monitoring, Performance Tuning, and Troubleshooting

Understanding cloud-init architecture

Cloud-init works with the concept of boot stages because it needs fine and granular control over what happens to the system during boot. The prerequisite for cloud-init would, of course, be a cloud-init image. From the documentation available at https://cloudinit.readthedocs.io, we can learn that there are five stages to a cloud-init boot:

  • The generator is the first one, and the simplest one: it will determine whether we are even trying to run cloud-init, and based on that, whether it should enable or disable the processing of data files. Cloud-init will not run if there are kernel command-line directives to disable it, or if a file called /etc/cloud/cloud-init.diabled exists. For more information on this and all the other things in this chapter, please read the documentation (start at https://cloudinit.readthedocs.io/en/latest/topics/boot.html) since it contains much more detail about switches and different options that cloud-init supports...