Search icon CANCEL
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Conferences
Free Learning
Arrow right icon
Mastering KVM Virtualization
Mastering KVM Virtualization

Mastering KVM Virtualization: Dive in to the cutting edge techniques of Linux KVM virtualization, and build the virtualization solutions your datacentre demands

eBook
€24.99 €36.99
Paperback
€45.99
Subscription
Free Trial
Renews at €18.99p/m

What do you get with Print?

Product feature icon Instant access to your digital eBook copy whilst your Print order is Shipped
Product feature icon Paperback book shipped to your preferred address
Product feature icon Download this book in EPUB and PDF formats
Product feature icon Access this title in our online reader with advanced features
Product feature icon DRM FREE - Read whenever, wherever and however you want
Table of content icon View table of contents Preview book icon Preview Book

Mastering KVM Virtualization

Chapter 2. KVM Internals

In this chapter, we will discuss the important data structures and the internal implementation of libvirt, QEMU, and KVM. Then we will dive into the execution flow of a vCPU in the KVM context.

In this chapter, we will cover:

  • The internal workings of libvirt, QEMU, and KVM.
  • Important data structures and code paths of libvirt, QEMU, and KVM.
  • Execution flow of vCPUs
  • How all these communicate with each other to provide virtualization

Getting acquainted with libvirt and its implementation

As discussed in a previous chapter, there is an extra management layer called libvirt which can talk to various hypervisors (for example: KVM/QEMU, LXC, OpenVZ, UML, and so on) underlying it. libvirt is an open source Application Programming Interface (API). At the same time, it is a daemon and a management tool for managing different hypervisors as mentioned. libvirt is in use by various virtualization programs and platforms; for example, graphical user interfaces are provided by GNOME boxes and virt-manager (http://virt-manager.org/). Don't confuse this with virtual machine monitor/VMM which we discussed in Chapter 1, Understanding Linux Virtualization.

The command line client interface of libvirt is the binary called virsh. libvirt is also used by other higher-level management tools, such as oVirt (www.ovirt.org):

Getting acquainted with libvirt and its implementation

Most people think that libvirt is restricted to a single node or local node where it is running; it's not true...

Internal workings of libvirt

Let me give some details about the following libvirt source code. If you really want to know more about the implementation, it is good to poke around in the libvirt source code. Get the libvirt source code from the libvirt Git repository:

[root@node]# git clone git://libvirt.org/libvirt.git

Once you clone the repo, you can see the following hierarchy of files in the repo:

Internal workings of libvirt

libvirt code is based on the C programming language; however, libvirt has language bindings in different languages such as C#, Java, OCaml, Perl, PHP, Python, Ruby, and so on. For more details on these bindings, please refer to: https://libvirt.org/bindings.html. The main (and few) directories in the source code are docs, daemon, src, and so on. The libvirt project is well documented and the documentation is available in the source code repo and also at http://libvirt.org.

Let us move on. If we look at the libvirt internals, we can see libvirt operates or starts the connection path based on driver...

Time to think more about QEMU

Quick Emulator (QEMU) was written by Fabrice Bellard (creator of FFmpeg), and is free software and mainly licensed under GNU General Public License (GPL).

QEMU is a generic and open source machine emulator and virtualizer. When used as a machine emulator, QEMU can run OSs and programs made for one machine (for example: an ARM board) on a different machine (for example: your own PC). By using dynamic translation, it achieves very good performance (see www.QEMU.org).

Let me rephrase the preceding paragraph and give a more specific explanation. QEMU is actually a hosted hypervisor/VMM that performs hardware virtualization. Are you confused? If yes, don't worry. You will get a better picture by the end of this chapter, especially when you go through each of the interrelated components and correlate the entire path used here to perform virtualization. QEMU can act as an Emulator or Virtualizer:

  • Qemu as an Emulator: In Chapter 1, Understanding Linux Virtualization...

KVM in action

Time to discuss KVM! The fundamentals KVM developers followed were the same as the Linux kernel: "Don't reinvent the wheel". That said, they didn't try to change the kernel code to make a hypervisor; rather, the code was developed by following the new hardware assistance in virtualization (VMX and SVM) from hardware vendors as a loadable kernel module. There is a common kernel module called kvm.ko and there are hardware-based kernel modules such as kvm-intel.ko (Intel-based systems) or kvm-amd.ko (AMD-based systems). Accordingly, KVM will load the kvm-intel.ko (if the vmx flag is present) or kvm-amd.ko (if the svm flag is present) modules. This turns the Linux kernel into a hypervisor, thus achieving virtualization. The KVM is developed by qumranet and it has been part of the Linux kernel since version 2.6.20. Later qumranet was acquired by Red Hat.

KVM exposes a device file called /dev/kvm to applications to make use of the ioctls() provided. QEMU makes...

Anonymous inodes and file structures

Previously, when we discussed QEMU, we said the Linux kernel allocates file structures and sets its f_ops and anonymous inodes. Let's look into the kvm-main.c file:

static struct file_operations kvm_chardev_ops = {
      .unlocked_ioctl = kvm_dev_ioctl,
      .compat_ioctl   = kvm_dev_ioctl,
      .llseek         = noop_llseek,
};
 kvm_dev_ioctl () 
    switch (ioctl) {
          case KVM_GET_API_VERSION:
              if (arg)
                    	goto out;
              r = KVM_API_VERSION;
              break;
          case KVM_CREATE_VM:
              r = kvm_dev_ioctl_create_vm(arg);
              break;
          case KVM_CHECK_EXTENSION:
              r = kvm_vm_ioctl_check_extension_generic(NULL, arg);
              break;
          case KVM_GET_VCPU_MMAP_SIZE:
  .    …..
}

As such as kvm_chardev_fops, there exist kvm_vm_fops and kvm_vcpu_fops:

static struct file_operations kvm_vm_fops = {
        .release        = kvm_vm_release,
...

Getting acquainted with libvirt and its implementation


As discussed in a previous chapter, there is an extra management layer called libvirt which can talk to various hypervisors (for example: KVM/QEMU, LXC, OpenVZ, UML, and so on) underlying it. libvirt is an open source Application Programming Interface (API). At the same time, it is a daemon and a management tool for managing different hypervisors as mentioned. libvirt is in use by various virtualization programs and platforms; for example, graphical user interfaces are provided by GNOME boxes and virt-manager (http://virt-manager.org/). Don't confuse this with virtual machine monitor/VMM which we discussed in Chapter 1, Understanding Linux Virtualization.

The command line client interface of libvirt is the binary called virsh. libvirt is also used by other higher-level management tools, such as oVirt (www.ovirt.org):

Most people think that libvirt is restricted to a single node or local node where it is running; it's not true. libvirt...

Internal workings of libvirt


Let me give some details about the following libvirt source code. If you really want to know more about the implementation, it is good to poke around in the libvirt source code. Get the libvirt source code from the libvirt Git repository:

[root@node]# git clone git://libvirt.org/libvirt.git

Once you clone the repo, you can see the following hierarchy of files in the repo:

libvirt code is based on the C programming language; however, libvirt has language bindings in different languages such as C#, Java, OCaml, Perl, PHP, Python, Ruby, and so on. For more details on these bindings, please refer to: https://libvirt.org/bindings.html. The main (and few) directories in the source code are docs, daemon, src, and so on. The libvirt project is well documented and the documentation is available in the source code repo and also at http://libvirt.org.

Let us move on. If we look at the libvirt internals, we can see libvirt operates or starts the connection path based on driver...

Left arrow icon Right arrow icon

Key benefits

  • Become an expert in Linux virtualization
  • Migrate your virtualized datacenter to the cloud
  • Find out how to build a large scale virtualization solution that will transform your organization

Description

A robust datacenter is essential for any organization – but you don’t want to waste resources. With KVM you can virtualize your datacenter, transforming a Linux operating system into a powerful hypervisor that allows you to manage multiple OS with minimal fuss. This book doesn’t just show you how to virtualize with KVM – it shows you how to do it well. Written to make you an expert on KVM, you’ll learn to manage the three essential pillars of scalability, performance and security – as well as some useful integrations with cloud services such as OpenStack. From the fundamentals of setting up a standalone KVM virtualization platform, and the best tools to harness it effectively, including virt-manager, and kimchi-project, everything you do is built around making KVM work for you in the real-world, helping you to interact and customize it as you need it. With further guidance on performance optimization for Microsoft Windows and RHEL virtual machines, as well as proven strategies for backup and disaster recovery, you’ll can be confident that your virtualized data center is working for your organization – not hampering it. Finally, the book will empower you to unlock the full potential of cloud through KVM. Migrating your physical machines to the cloud can be challenging, but once you’ve mastered KVM, it’s a little easie.

Who is this book for?

Linux administrators – if you want to build incredible, yet manageable virtualization solutions with KVM this is the book to get you there. It will help you apply what you already know to some tricky virtualization tasks.

What you will learn

  • Explore the ecosystem of tools that support Linux virtualization
  • Find out why KVM offers you a smarter way to unlock the potential of virtualization
  • Implement KVM virtualization using oVirt
  • Explore the KVM architecture – so you can manage, scale and optimize it with ease
  • Migrate your virtualized datacenter to the cloud for truly resource-efficient computing
  • Find out how to integrate OpenStack with KVM to take full control of the cloud
Estimated delivery fee Deliver to Bulgaria

Premium delivery 7 - 10 business days

€25.95
(Includes tracking information)

Product Details

Country selected
Publication date, Length, Edition, Language, ISBN-13
Publication date : Aug 19, 2016
Length: 468 pages
Edition : 1st
Language : English
ISBN-13 : 9781784399054
Vendor :
Red Hat
Tools :

What do you get with Print?

Product feature icon Instant access to your digital eBook copy whilst your Print order is Shipped
Product feature icon Paperback book shipped to your preferred address
Product feature icon Download this book in EPUB and PDF formats
Product feature icon Access this title in our online reader with advanced features
Product feature icon DRM FREE - Read whenever, wherever and however you want
Estimated delivery fee Deliver to Bulgaria

Premium delivery 7 - 10 business days

€25.95
(Includes tracking information)

Product Details

Publication date : Aug 19, 2016
Length: 468 pages
Edition : 1st
Language : English
ISBN-13 : 9781784399054
Vendor :
Red Hat
Tools :

Packt Subscriptions

See our plans and pricing
Modal Close icon
€18.99 billed monthly
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Simple pricing, no contract
€189.99 billed annually
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Choose a DRM-free eBook or Video every month to keep
Feature tick icon PLUS own as many other DRM-free eBooks or Videos as you like for just €5 each
Feature tick icon Exclusive print discounts
€264.99 billed in 18 months
Feature tick icon Unlimited access to Packt's library of 7,000+ practical books and videos
Feature tick icon Constantly refreshed with 50+ new titles a month
Feature tick icon Exclusive Early access to books as they're written
Feature tick icon Solve problems while you work with advanced search and reference features
Feature tick icon Offline reading on the mobile app
Feature tick icon Choose a DRM-free eBook or Video every month to keep
Feature tick icon PLUS own as many other DRM-free eBooks or Videos as you like for just €5 each
Feature tick icon Exclusive print discounts

Frequently bought together


Stars icon
Total 128.97
Practical Linux Security Cookbook
€36.99
KVM Virtualization Cookbook
€45.99
Mastering KVM Virtualization
€45.99
Total 128.97 Stars icon

Table of Contents

16 Chapters
1. Understanding Linux Virtualization Chevron down icon Chevron up icon
2. KVM Internals Chevron down icon Chevron up icon
3. Setting Up Standalone KVM Virtualization Chevron down icon Chevron up icon
4. Getting Started with libvirt and Creating Your First Virtual Machines Chevron down icon Chevron up icon
5. Network and Storage Chevron down icon Chevron up icon
6. Virtual Machine Lifecycle Management Chevron down icon Chevron up icon
7. Templates and Snapshots Chevron down icon Chevron up icon
8. Kimchi – An HTML5-Based Management Tool for KVM/libvirt Chevron down icon Chevron up icon
9. Software-Defined Networking for KVM Virtualization Chevron down icon Chevron up icon
10. Installing and Configuring the Virtual Datacenter Using oVirt Chevron down icon Chevron up icon
11. Starting Your First Virtual Machine in oVirt Chevron down icon Chevron up icon
12. Deploying OpenStack Private Cloud backed by KVM Virtualization Chevron down icon Chevron up icon
13. Performance Tuning and Best Practices in KVM Chevron down icon Chevron up icon
14. V2V and P2V Migration Tools Chevron down icon Chevron up icon
A. Converting a Virtual Machine into a Hypervisor Chevron down icon Chevron up icon
Index Chevron down icon Chevron up icon

Customer reviews

Top Reviews
Rating distribution
Full star icon Full star icon Full star icon Full star icon Half star icon 4.2
(16 Ratings)
5 star 62.5%
4 star 6.3%
3 star 18.8%
2 star 12.5%
1 star 0%
Filter icon Filter
Top Reviews

Filter reviews by




Amazon Customer Jan 04, 2019
Full star icon Full star icon Full star icon Full star icon Full star icon 5
Excellent book!
Amazon Verified review Amazon
Jivan Nisargam Mar 10, 2017
Full star icon Full star icon Full star icon Full star icon Full star icon 5
I read the whole book and found so much information on topics like KVM internal, Software Defined Networking, Ovirt, Openstack, Performance issues, V2V/P2V. I have never found a single book which covers all topics related to KVM. This book deserves more then 5 stars.
Amazon Verified review Amazon
D Caughey Apr 05, 2017
Full star icon Full star icon Full star icon Full star icon Full star icon 5
The best KVM book out there to get a really good foundation and pretty good knowledge. Pretty well written but would have liked more in depth examples. Chap1 is far too long and is pointed directly at developers.
Amazon Verified review Amazon
Amazon Customer May 20, 2017
Full star icon Full star icon Full star icon Full star icon Full star icon 5
Awesome Book About Linux Virtualiaztion, KVM , Qemu, libvirt, Ovirt and its integration.
Amazon Verified review Amazon
Joao Rodrigues May 23, 2017
Full star icon Full star icon Full star icon Full star icon Full star icon 5
This book is a very valuable resource! It takes you from the inner works of Linux KVM, what happens under the hood, explores the different types of hypervisors, and sets out to explain how and why Linux is a very solid choice for the datacentre virtualization layer. It takes the reader from the most basic level, and builds up the knowledge to explore more advanced features such as SDN, OpenStack, as well as operational topics such as VM Lifecycle management. Everything is very clearly explained and nicely structured! Five stars! :-)
Amazon Verified review Amazon
Get free access to Packt library with over 7500+ books and video courses for 7 days!
Start Free Trial

FAQs

What is the delivery time and cost of print book? Chevron down icon Chevron up icon

Shipping Details

USA:

'

Economy: Delivery to most addresses in the US within 10-15 business days

Premium: Trackable Delivery to most addresses in the US within 3-8 business days

UK:

Economy: Delivery to most addresses in the U.K. within 7-9 business days.
Shipments are not trackable

Premium: Trackable delivery to most addresses in the U.K. within 3-4 business days!
Add one extra business day for deliveries to Northern Ireland and Scottish Highlands and islands

EU:

Premium: Trackable delivery to most EU destinations within 4-9 business days.

Australia:

Economy: Can deliver to P. O. Boxes and private residences.
Trackable service with delivery to addresses in Australia only.
Delivery time ranges from 7-9 business days for VIC and 8-10 business days for Interstate metro
Delivery time is up to 15 business days for remote areas of WA, NT & QLD.

Premium: Delivery to addresses in Australia only
Trackable delivery to most P. O. Boxes and private residences in Australia within 4-5 days based on the distance to a destination following dispatch.

India:

Premium: Delivery to most Indian addresses within 5-6 business days

Rest of the World:

Premium: Countries in the American continent: Trackable delivery to most countries within 4-7 business days

Asia:

Premium: Delivery to most Asian addresses within 5-9 business days

Disclaimer:
All orders received before 5 PM U.K time would start printing from the next business day. So the estimated delivery times start from the next day as well. Orders received after 5 PM U.K time (in our internal systems) on a business day or anytime on the weekend will begin printing the second to next business day. For example, an order placed at 11 AM today will begin printing tomorrow, whereas an order placed at 9 PM tonight will begin printing the day after tomorrow.


Unfortunately, due to several restrictions, we are unable to ship to the following countries:

  1. Afghanistan
  2. American Samoa
  3. Belarus
  4. Brunei Darussalam
  5. Central African Republic
  6. The Democratic Republic of Congo
  7. Eritrea
  8. Guinea-bissau
  9. Iran
  10. Lebanon
  11. Libiya Arab Jamahriya
  12. Somalia
  13. Sudan
  14. Russian Federation
  15. Syrian Arab Republic
  16. Ukraine
  17. Venezuela
What is custom duty/charge? Chevron down icon Chevron up icon

Customs duty are charges levied on goods when they cross international borders. It is a tax that is imposed on imported goods. These duties are charged by special authorities and bodies created by local governments and are meant to protect local industries, economies, and businesses.

Do I have to pay customs charges for the print book order? Chevron down icon Chevron up icon

The orders shipped to the countries that are listed under EU27 will not bear custom charges. They are paid by Packt as part of the order.

List of EU27 countries: www.gov.uk/eu-eea:

A custom duty or localized taxes may be applicable on the shipment and would be charged by the recipient country outside of the EU27 which should be paid by the customer and these duties are not included in the shipping charges been charged on the order.

How do I know my custom duty charges? Chevron down icon Chevron up icon

The amount of duty payable varies greatly depending on the imported goods, the country of origin and several other factors like the total invoice amount or dimensions like weight, and other such criteria applicable in your country.

For example:

  • If you live in Mexico, and the declared value of your ordered items is over $ 50, for you to receive a package, you will have to pay additional import tax of 19% which will be $ 9.50 to the courier service.
  • Whereas if you live in Turkey, and the declared value of your ordered items is over € 22, for you to receive a package, you will have to pay additional import tax of 18% which will be € 3.96 to the courier service.
How can I cancel my order? Chevron down icon Chevron up icon

Cancellation Policy for Published Printed Books:

You can cancel any order within 1 hour of placing the order. Simply contact customercare@packt.com with your order details or payment transaction id. If your order has already started the shipment process, we will do our best to stop it. However, if it is already on the way to you then when you receive it, you can contact us at customercare@packt.com using the returns and refund process.

Please understand that Packt Publishing cannot provide refunds or cancel any order except for the cases described in our Return Policy (i.e. Packt Publishing agrees to replace your printed book because it arrives damaged or material defect in book), Packt Publishing will not accept returns.

What is your returns and refunds policy? Chevron down icon Chevron up icon

Return Policy:

We want you to be happy with your purchase from Packtpub.com. We will not hassle you with returning print books to us. If the print book you receive from us is incorrect, damaged, doesn't work or is unacceptably late, please contact Customer Relations Team on customercare@packt.com with the order number and issue details as explained below:

  1. If you ordered (eBook, Video or Print Book) incorrectly or accidentally, please contact Customer Relations Team on customercare@packt.com within one hour of placing the order and we will replace/refund you the item cost.
  2. Sadly, if your eBook or Video file is faulty or a fault occurs during the eBook or Video being made available to you, i.e. during download then you should contact Customer Relations Team within 14 days of purchase on customercare@packt.com who will be able to resolve this issue for you.
  3. You will have a choice of replacement or refund of the problem items.(damaged, defective or incorrect)
  4. Once Customer Care Team confirms that you will be refunded, you should receive the refund within 10 to 12 working days.
  5. If you are only requesting a refund of one book from a multiple order, then we will refund you the appropriate single item.
  6. Where the items were shipped under a free shipping offer, there will be no shipping costs to refund.

On the off chance your printed book arrives damaged, with book material defect, contact our Customer Relation Team on customercare@packt.com within 14 days of receipt of the book with appropriate evidence of damage and we will work with you to secure a replacement copy, if necessary. Please note that each printed book you order from us is individually made by Packt's professional book-printing partner which is on a print-on-demand basis.

What tax is charged? Chevron down icon Chevron up icon

Currently, no tax is charged on the purchase of any print book (subject to change based on the laws and regulations). A localized VAT fee is charged only to our European and UK customers on eBooks, Video and subscriptions that they buy. GST is charged to Indian customers for eBooks and video purchases.

What payment methods can I use? Chevron down icon Chevron up icon

You can pay with the following card types:

  1. Visa Debit
  2. Visa Credit
  3. MasterCard
  4. PayPal
What is the delivery time and cost of print books? Chevron down icon Chevron up icon

Shipping Details

USA:

'

Economy: Delivery to most addresses in the US within 10-15 business days

Premium: Trackable Delivery to most addresses in the US within 3-8 business days

UK:

Economy: Delivery to most addresses in the U.K. within 7-9 business days.
Shipments are not trackable

Premium: Trackable delivery to most addresses in the U.K. within 3-4 business days!
Add one extra business day for deliveries to Northern Ireland and Scottish Highlands and islands

EU:

Premium: Trackable delivery to most EU destinations within 4-9 business days.

Australia:

Economy: Can deliver to P. O. Boxes and private residences.
Trackable service with delivery to addresses in Australia only.
Delivery time ranges from 7-9 business days for VIC and 8-10 business days for Interstate metro
Delivery time is up to 15 business days for remote areas of WA, NT & QLD.

Premium: Delivery to addresses in Australia only
Trackable delivery to most P. O. Boxes and private residences in Australia within 4-5 days based on the distance to a destination following dispatch.

India:

Premium: Delivery to most Indian addresses within 5-6 business days

Rest of the World:

Premium: Countries in the American continent: Trackable delivery to most countries within 4-7 business days

Asia:

Premium: Delivery to most Asian addresses within 5-9 business days

Disclaimer:
All orders received before 5 PM U.K time would start printing from the next business day. So the estimated delivery times start from the next day as well. Orders received after 5 PM U.K time (in our internal systems) on a business day or anytime on the weekend will begin printing the second to next business day. For example, an order placed at 11 AM today will begin printing tomorrow, whereas an order placed at 9 PM tonight will begin printing the day after tomorrow.


Unfortunately, due to several restrictions, we are unable to ship to the following countries:

  1. Afghanistan
  2. American Samoa
  3. Belarus
  4. Brunei Darussalam
  5. Central African Republic
  6. The Democratic Republic of Congo
  7. Eritrea
  8. Guinea-bissau
  9. Iran
  10. Lebanon
  11. Libiya Arab Jamahriya
  12. Somalia
  13. Sudan
  14. Russian Federation
  15. Syrian Arab Republic
  16. Ukraine
  17. Venezuela