Install KVM in 5 steps

The distribution use for this tutorial is Fedora 18, and can be applied on Centos/Rhel 6+

Step 1: Check if your processor have hardware virtualization extension

[root@localhost ~]# egrep -q "(vmx|svm)" /proc/cpuinfo && echo OK || NOK
If "OK" you can continue, else "sorry try another virtualization solution".

Step 2: Install KVM itself with it's tools

[root@localhost ~]# yum groupinstall virtualization

Step 3: Check if all the required modules are loaded

[root@localhost ~]# lsmod | grep kvm
kvm_intel 138567 0
kvm 429349 1 kvm_intel

if you have no results, manually load:

[root@localhost ~]# modprobe kvm

If at this step, kvm_intel not appear, this means that you have to enable the CPU virtualization extension in the BIOS (Intel VT-x or AMD-V).

You can see this on kernel messages:

[root@localhost ~]# grep kvm /var/log/messages
kernel: [ 15.331262] kvm: disabled by bios

Step 4: Start and enable the libvirtd daemon

[root@localhost ~]# systemctl start libvirtd.service
[root@localhost ~]# service libvirtd start      #on Centos/Rhel6
[root@localhost ~]# systemctl enable libvirtd.service
[root@localhost ~]# chkconfig libvirtd on      #on Centos/Rhel6

Step 5: Play with GUI virtual manager

[root@localhost ~]# virt-manager