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Linux KVM

KVM consists of a loadable kernel module, kvm.ko, that provides the core virtualization infrastructure and a processor specific module, kvm-intel.ko or kvm-amd.ko. Below diagram illustrates how the KVM hypervisor virtualizes the compute resources for Linux on KVM.

Installation - Step1: Verification

cat /proc/cpuinfo | egrep --color "vmx|svm"
lscpu | grep Virtualization
  • Step2: Install libvirt on Centos 9 Run Command:
sudo dnf groupinstall "Virtualization Host" -y
sudo dnf install epel-release yum-utils -y
sudo dnf install -y qemu-kvm libvirt ibvirt-devel libvirt-client virt-install virt-viewer
sudo dnf install -y libguestfs-tools libguestfs-xfs virt-top
sudo dnf install -y bridge-utils   
sudo dnf install  libvirt-python virt-manager
  • Step3: Start libvirt
sudo systemctl start libvirtd
sudo systemctl status libvirt
  • Step4: Check if kernel modules are loaded
$ lsmod | grep kvm

kvm_intel             446464  0
kvm                  1392640  1 kvm_intel
irqbypass              12288  1 kvm

Linux Bridge

The Linux bridge virbr0 is created at the time of installation and can be used to create Virtual Machines that doesn’t need external IP connectivity. It uses NAT to give VMs internet access.

A Linux bridge is a kernel module that behaves like a network switch, forwarding packets between interfaces that are connected to it. It's usually used for forwarding packets on routers, on gateways, or between VMs and network namespaces on a host.

$ ip a
$ ip link show
$ brctl show