Install KVM Virtualization on Centos 7 and RHEL 7

Description: KVM is an open source hardware virtualization software through which we can create and run multiple Linux based and windows based virtual machines simultaneously. KVM known as Kernel based Virtual Machine because when we install KVM package then KVM module is loaded into the current kernel and turns our Linux machine into a hyper-visor.

Before installation, we need to check CPU supports Hardware Virtualization. To check use below command:

[root@localhost ~] # grep -E '(vmx|svm)' /proc/cpuinfo

Output should be either vmx or svm, Otherwise CPU does not support Virtualization

Procedure:

First install KVM and its associate packages 

[root@localhost ~] # yum install qemu-kvm qemu-img virt-manager libvirt libvirt-python libvirt-client virt-install virt-viewer bridge-utils

After installation enable and start libvirtd service

[root@localhost ~] # systemctl start libvirtd

[root@localhost ~] # systemctl enable libvirtd 

Verify KVM Installation:

[root@localhost ~] # lsmod | grep -i kvm

kvm_intel             162153  0

kvm                   525409  1 kvm_intel

Configure Bridge Interface: Before start creating VM you need to configure bridge interface is required if you want to access virtual machine from outside of your network

[root@localhost ~]# cd /etc/sysconfig/network-scripts/

[root@localhost network-scripts]# cp ifcfg-eth0 ifcfg-br0

Edit the Interface file and set followings:

[root@localhost network-scripts]# vi ifcfg-eth0

TYPE=Ethernet

BOOTPROTO=static

DEVICE=eth0

ONBOOT=yes

BRIDGE=br0

Edit the Bridge file (ifcfg-br0) and set the followings:

[root@localhost network-scripts] # vi ifcfg-br0

TYPE=Bridge

BOOTPROTO=static

DEVICE=br0

ONBOOT=yes

IPADDR=10.10.10.1

NETMASK=255.255.255.0

GATEWAY=10.10.10.11

DNS1=10.10.10.11

Replace the IP address and DNS server details as per your setup.

After making changes Restart network service 

[root@localhost ~] # systemctl restart network

Check the Bridge interface using below command :

[root@localhost ~] # ip addr show br0

Start creating virtual machine using by 'virt-install' or virt-manager [GUI Tool]

Go to file option, Click on "New Virtual Machine"

Specify ISO file location and provide RAM and CPU as per your requirement. 

Click on Finish to create Virtual Machine

Creating a virtual Machine from Command Line:

[root@localhost ~] # virt-install --name=Ubuntu-16-04 --file=/var/lib/libvirt/images/ubuntu16-04.dsk --file-size=20 --nonsparse --graphics spice --vcpus=2 --ram=2048 --cdrom=ubuntu-16.04-server-amd64.iso --network bridge=br0 --os-type=linux --os-variant=generic

Starting install...

Allocating 'ubuntu16-04.dsk'               | 20 GB 00:00:00

Creating domain...