QEMU Virtualization

Commands

show all VMs

virsh list --all

stop VM

virsh shutdown myhost1

start VM

virsh autostart myhost1

reboot VM

virsh reboot myhost1

reset VM (hard reset - not safe)

virsh reset myhost1

delete VM

virsh shutdown myhost1

virsh undefine myhost1

virsh pool-destroy myhost1

rm -ri /path/to/images/myhost1

 


Get VM info

virsh dominfo vmName

virsh dominfo centos7-vm1


show VM images

virt-builder --list

build an Ubuntu VM

virt-builder ubuntu-16.04 \--size=20G --format qcow2 -o /var/lib/libvirt/images/ncbz01-disk01.qcow2 \--hostname ncbz01
--network --timezone Asia/Kolkata \--firstboot-command "dpkg-reconfigure openssh-server" \--edit '/etc/default/grub:s/^GRUB_CMDLINE_LINUX_DEFAULT=.*/GRUB_CMDLINE_LINUX_DEFAULT="console=tty0 console=ttyS0,115200n8"/' \--run-command update-grub
 

Install Win10 VM on a Centos7 host

check if virtualization enabled in BIOS

egrep '(vmx|svm)' /proc/cpuinfo

if above output shows VMX or SVM, then virt is supported

disable SELinux

sudo setenforce 0

install Xwindow for Virt Manager GUI

yum install "@X Window System" xorg-x11-xauth xorg-x11-fonts-* xorg-x11-utils -y

check if kvm module is loaded

lsmod | grep kvm (reboot if now loaded)

install virt pkgs

yum install qemu-kvm libvirt libvirt-python libguestfs-tools virt-installsystemctl enable libvirtdsystemctl start libvirtd

Configure bridged networking

By default dhcpd based network bridge configured by libvirtd. You can verify that with the following commands:

{root@centos-7:~ }# brctl show{root@centos-7:~ }# virsh net-list

All VMs (guest machine) only have network access to other VMs on the same server. A private network 192.168.122.0/24 created for you. Verify it:

{root@centos-7:~ }# virsh net-dumpxml default

If you want your VMs avilable to other servers on your LAN, setup a a network bridge on the server that connected to the your LAN. Update your nic config file such as ifcfg-enp3s0 or em1:

{root@centos-7:~ }# vi /etc/sysconfig/network-scripts/enp3s0


Add line:

BRIDGE=br0

Edit /etc/sysconfig/network-scripts/ifcfg-br0 and add:

{root@centos-7:~ }# vi /etc/sysconfig/network-scripts/ifcfg-br0

Append the following:

DEVICE="br0"

# I am getting ip from DHCP server #

BOOTPROTO="dhcp"

IPV6INIT="yes"

IPV6_AUTOCONF="yes"

ONBOOT="yes"

TYPE="Bridge"

DELAY="0"

Restart the networking service (warning ssh command will disconnect, it is better to reboot the box):

{root@centos-7:~ }# systemctl restart NetworkManager


Verify it with brctl command:

{root@centos-7:~ }# brctl show

Create VM

copy Win10 ISO to Centos7 host (/mnt/hc/iso)

create Virtual Disk Image

qemu-img create -f qcow2 windows10.qcow2 40G

Install VM

virt-install \

  --name windows10 \

  --ram 32768 \

  --vcpus 4 \

  --os-type windows \

  --os-variant win10 \

  --virt-type kvm \

  --graphics spice \

  --disk path=windows10.qcow2,format=qcow2 \

  --cdrom /path/to/Win10.iso