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

Snapshots

A VM snapshot is a file-based representation of the system state at a particular point in time. The snapshot includes configuration and disk data. With a snapshot, you can revert a VM to a point in time, which means by taking a snapshot of a VM, you preserve its state and can easily revert to it in the future if needed.

Snapshots have many use cases, such as saving a VM's state before a potentially destructive operation. For example, suppose you want to make some changes on your existing web server VM, which is running fine at the moment, but you are not certain if the changes you are planning to make are going to work or will break something. In that case, you can take a snapshot of the VM before doing the intended configuration changes, and if something goes wrong, you can easily revert to the previous working state of the VM by restoring the snapshot.

libvirt supports taking live snapshots. You can take a snapshot of a VM while the guest is running. However...