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

iSCSI and SAN storage

Using iSCSI for virtual machine storage has long been the regular thing to do. Even if you take into account the fact that iSCSI isn't the most efficient way to approach storage, it's still so widely accepted that you'll find it everywhere. Efficiency is compromised for two reasons:

  • iSCSI encapsulates SCSI commands into regular IP packages, which means segmentation and overhead as IP packages have a pretty large header, which means less efficiency.
  • Even worse, it's TCP-based, which means that there are sequence numbers and retransmissions, which can lead to queueing and latency, and the bigger the environment is, the more you usually feel these effects affect your virtual machine performance.

That being said, the fact that it's based on an Ethernet stack makes it easier to deploy iSCSI-based solutions, while at the same time offering some unique challenges. For example, sometimes it's difficult to explain to a customer...