What is virtualization?

  • Virtualization describes a technology in which an application, guest operating system or data storage is abstracted away from the true underlying hardware or software.

Host Machine / OS

Virtualization Layer

Guest OS

Guest OS

Guest OS




Types of Virtualization - Hypervisor

Type-1 Hypervisor

  • Native and Bare-Metal Hypervisor
  • Software that is run as the OS

Type-2 Hypervisor

  • Hosted Hypervisor
  • Software that runs on top of another host OS

Types of Virtualization - Classes

  • Hardware Virtualization
    • Native / Bare-Metal
    • Hosted
  • OS-Level Virtualization
  • Desktop Virtualization
  • Application Virtualization
  • Network Virtualization


  • KVM (Kernel-based Virtual Machine) (Hardware Virtualization, Type 2 - Hosted)
  • VirtualBox (Hardware Virtualization, Type 2 - Hosted)
  • VMWare Workstation (Hardware Virtualization, Type 2 - Hosted)
  • VMWare vSphere Hypervisor (ESXi) (Hardware Virtualization, Type 1 - Native)
  • QEMU (Hardware Virtualization, Type 2 - Hosted)
  • CoreOS (OS-level Virtualization, cgroups / docker / rkt)
  • Citrix XenApp (Desktop Virtualization)

In Production

  • When creating many virtual machines, we need to have utilities to help us automate the process of creating, provisioning, and running virtual machines.

Some solutions:

  • Scripting (Vagrant)
  • Hypervisor CLI Tools (virsh, vagrant)
  • GUI (vSphere Web Client, Virtual Machine Manager,...)

Virtual Machine Manager (We use this in the ACM)

  • Created by Red Hat
  • Can be used to manage, KVM, QEMU, Xen, and LXC
  • Used to manage hypervisors remotely.
  • Basically a front-end to virsh.


$ virsh

Welcome to virsh, the virtualization interactive terminal.

Type: 'help' for help with commands

'quit' to quit

virsh # help

Grouped commands:

Domain Management (help keyword 'domain'):

attach-device attach device from an XML file

attach-disk attach disk device

attach-interface attach network interface

autostart autostart a domain

blkdeviotune Set or query a block device I/O tuning parameters.

blkiotune Get or set blkio parameters

blockcommit Start a block commit operation.

blockcopy Start a block copy operation.

blockjob Manage active block operations

blockpull Populate a disk from its backing image.

blockresize Resize block device of domain.

change-media Change media of CD or floppy drive

console connect to the guest console

cpu-baseline compute baseline CPU

cpu-compare compare host CPU with a CPU described by an XML file

cpu-stats show domain cpu statistics

create create a domain from an XML file

define define (but don't start) a domain from an XML file

desc show or set domain's description or title

destroy destroy (stop) a domain

detach-device detach device from an XML file

detach-disk detach disk device

detach-interface detach network interface

domdisplay domain display connection URI

domfsfreeze Freeze domain's mounted filesystems.

domfsthaw Thaw domain's mounted filesystems.

domfsinfo Get information of domain's mounted filesystems.

domfstrim Invoke fstrim on domain's mounted filesystems.

domhostname print the domain's hostname

domid convert a domain name or UUID to domain id

domif-setlink set link state of a virtual interface

domiftune get/set parameters of a virtual interface

domjobabort abort active domain job

domjobinfo domain job information

domname convert a domain id or UUID to domain name

domrename rename a domain

dompmsuspend suspend a domain gracefully using power management functions

dompmwakeup wakeup a domain from pmsuspended state

domuuid convert a domain name or id to domain UUID

domxml-from-native Convert native config to domain XML

domxml-to-native Convert domain XML to native config

dump dump the core of a domain to a file for analysis

dumpxml domain information in XML

edit edit XML configuration for a domain

event Domain Events

inject-nmi Inject NMI to the guest

iothreadinfo view domain IOThreads

iothreadpin control domain IOThread affinity

iothreadadd add an IOThread to the guest domain

iothreaddel delete an IOThread from the guest domain

send-key Send keycodes to the guest

send-process-signal Send signals to processes

lxc-enter-namespace LXC Guest Enter Namespace

managedsave managed save of a domain state

managedsave-remove Remove managed save of a domain

memtune Get or set memory parameters

perf Get or set perf event

metadata show or set domain's custom XML metadata

migrate migrate domain to another host

migrate-setmaxdowntime set maximum tolerable downtime

migrate-compcache get/set compression cache size

migrate-setspeed Set the maximum migration bandwidth

migrate-getspeed Get the maximum migration bandwidth

migrate-postcopy Switch running migration from pre-copy to post-copy

numatune Get or set numa parameters

qemu-attach QEMU Attach

qemu-monitor-command QEMU Monitor Command

qemu-monitor-event QEMU Monitor Events

qemu-agent-command QEMU Guest Agent Command

reboot reboot a domain

reset reset a domain

restore restore a domain from a saved state in a file

resume resume a domain

save save a domain state to a file

save-image-define redefine the XML for a domain's saved state file

save-image-dumpxml saved state domain information in XML

save-image-edit edit XML for a domain's saved state file

schedinfo show/set scheduler parameters

screenshot take a screenshot of a current domain console and store it into a file

set-user-password set the user password inside the domain

setmaxmem change maximum memory limit

setmem change memory allocation

setvcpus change number of virtual CPUs

shutdown gracefully shutdown a domain

start start a (previously defined) inactive domain

suspend suspend a domain

ttyconsole tty console

undefine undefine a domain

update-device update device from an XML file

vcpucount domain vcpu counts

vcpuinfo detailed domain vcpu information

vcpupin control or query domain vcpu affinity

emulatorpin control or query domain emulator affinity

vncdisplay vnc display

guestvcpus query or modify state of vcpu in the guest (via agent)

Domain Monitoring (help keyword 'monitor'):

domblkerror Show errors on block devices

domblkinfo domain block device size information

domblklist list all domain blocks

domblkstat get device block stats for a domain

domcontrol domain control interface state

domif-getlink get link state of a virtual interface

domifaddr Get network interfaces' addresses for a running domain

domiflist list all domain virtual interfaces

domifstat get network interface stats for a domain

dominfo domain information

dommemstat get memory statistics for a domain

domstate domain state

domstats get statistics about one or multiple domains

domtime domain time

list list domains

Host and Hypervisor (help keyword 'host'):

allocpages Manipulate pages pool size

capabilities capabilities

cpu-models CPU models

domcapabilities domain capabilities

freecell NUMA free memory

freepages NUMA free pages

hostname print the hypervisor hostname

maxvcpus connection vcpu maximum

node-memory-tune Get or set node memory parameters

nodecpumap node cpu map

nodecpustats Prints cpu stats of the node.

nodeinfo node information

nodememstats Prints memory stats of the node.

nodesuspend suspend the host node for a given time duration

sysinfo print the hypervisor sysinfo

uri print the hypervisor canonical URI

version show version

Interface (help keyword 'interface'):

iface-begin create a snapshot of current interfaces settings, which can be later committed (iface-commit) or restored (iface-rollback)

iface-bridge create a bridge device and attach an existing network device to it

iface-commit commit changes made since iface-begin and free restore point

iface-define define an inactive persistent physical host interface or modify an existing persistent one from an XML file

iface-destroy destroy a physical host interface (disable it / "if-down")

iface-dumpxml interface information in XML

iface-edit edit XML configuration for a physical host interface

iface-list list physical host interfaces

iface-mac convert an interface name to interface MAC address

iface-name convert an interface MAC address to interface name

iface-rollback rollback to previous saved configuration created via iface-begin

iface-start start a physical host interface (enable it / "if-up")

iface-unbridge undefine a bridge device after detaching its slave device

iface-undefine undefine a physical host interface (remove it from configuration)

Network Filter (help keyword 'filter'):

nwfilter-define define or update a network filter from an XML file

nwfilter-dumpxml network filter information in XML

nwfilter-edit edit XML configuration for a network filter

nwfilter-list list network filters

nwfilter-undefine undefine a network filter

Networking (help keyword 'network'):

net-autostart autostart a network

net-create create a network from an XML file

net-define define an inactive persistent virtual network or modify an existing persistent one from an XML file

net-destroy destroy (stop) a network

net-dhcp-leases print lease info for a given network

net-dumpxml network information in XML

net-edit edit XML configuration for a network

net-event Network Events

net-info network information

net-list list networks

net-name convert a network UUID to network name

net-start start a (previously defined) inactive network

net-undefine undefine a persistent network

net-update update parts of an existing network's configuration

net-uuid convert a network name to network UUID

Node Device (help keyword 'nodedev'):

nodedev-create create a device defined by an XML file on the node

nodedev-destroy destroy (stop) a device on the node

nodedev-detach detach node device from its device driver

nodedev-dumpxml node device details in XML

nodedev-list enumerate devices on this host

nodedev-reattach reattach node device to its device driver

nodedev-reset reset node device

nodedev-event Node Device Events

Secret (help keyword 'secret'):

secret-define define or modify a secret from an XML file

secret-dumpxml secret attributes in XML

secret-event Secret Events

secret-get-value Output a secret value

secret-list list secrets

secret-set-value set a secret value

secret-undefine undefine a secret

Snapshot (help keyword 'snapshot'):

snapshot-create Create a snapshot from XML

snapshot-create-as Create a snapshot from a set of args

snapshot-current Get or set the current snapshot

snapshot-delete Delete a domain snapshot

snapshot-dumpxml Dump XML for a domain snapshot

snapshot-edit edit XML for a snapshot

snapshot-info snapshot information

snapshot-list List snapshots for a domain

snapshot-parent Get the name of the parent of a snapshot

snapshot-revert Revert a domain to a snapshot

Storage Pool (help keyword 'pool'):

find-storage-pool-sources-as find potential storage pool sources

find-storage-pool-sources discover potential storage pool sources

pool-autostart autostart a pool

pool-build build a pool

pool-create-as create a pool from a set of args

pool-create create a pool from an XML file

pool-define-as define a pool from a set of args

pool-define define an inactive persistent storage pool or modify an existing persistent one from an XML file

pool-delete delete a pool

pool-destroy destroy (stop) a pool

pool-dumpxml pool information in XML

pool-edit edit XML configuration for a storage pool

pool-info storage pool information

pool-list list pools

pool-name convert a pool UUID to pool name

pool-refresh refresh a pool

pool-start start a (previously defined) inactive pool

pool-undefine undefine an inactive pool

pool-uuid convert a pool name to pool UUID

pool-event Storage Pool Events

Storage Volume (help keyword 'volume'):

vol-clone clone a volume.

vol-create-as create a volume from a set of args

vol-create create a vol from an XML file

vol-create-from create a vol, using another volume as input

vol-delete delete a vol

vol-download download volume contents to a file

vol-dumpxml vol information in XML

vol-info storage vol information

vol-key returns the volume key for a given volume name or path

vol-list list vols

vol-name returns the volume name for a given volume key or path

vol-path returns the volume path for a given volume name or key

vol-pool returns the storage pool for a given volume key or path

vol-resize resize a vol

vol-upload upload file contents to a volume

vol-wipe wipe a vol

Virsh itself (help keyword 'virsh'):

cd change the current directory

echo echo arguments

exit quit this interactive terminal

help print help

pwd print the current directory

quit quit this interactive terminal

connect (re)connect to hypervisor

virsh #


  • Vagrant is an open-source software product for building and maintaining portable virtual development environments.
  • Can make use of many hypervisor backends

Let’s create a Vagrant VM


  • VirtualBox
  • Vagrant

Your First Command:

vagrant init

This will create a base file defining your VM.

Let’s create a Vagrant VM - Part 2

Find a list of VM images here:

In your `VagrantFile`:

Vagrant.configure("2") do |config|
# The most common configuration options are documented and commented below.
# For a complete reference, please see the online documentation at

# Every Vagrant development environment requires a box. You can search for
# boxes at = "base" # Replace this line!!!!

I’ll be using `ubuntu/xenial64`

Let’s create a Vagrant VM - Part 3

In your terminal, use this command:

vagrant up

(Run this in the same directory as your Vagrantfile)

You should see something around the following:

Once it downloads, it will automatically start.

Let’s create a Vagrant VM - Part 4

Once it downloads, it will automatically start.

In your terminal, use this command:

vagrant ssh

(Run this in the same directory as your Vagrantfile)

You should see something around the following after setup:

Let’s create a Vagrant VM - Part 5

After running vagrant ssh:

To shutdown the VM, run:

Vagrant halt

Virtualization - 3/6/2017 - Google Slides