How to Install KVM on Ubuntu Linux

This brief tutorial shows students and new users how to install KVM on Ubuntu 20.04 | 18.04.

KVM (Kernel-based Virtual Machine) is an open-source full virtualization solution for Linux systems, including Ubuntu. Like VirtualBox, and VMware Workstation, KVM is a virtualization infrastructure for the Linux kernel that turns it into a hypervisor.

This brief tutorial shows students and new users how to install KVM kernel modules on the Ubuntu server to enable full virtualization.

If you can’t install VirtualBox or VMware Workstation virtualization solutions on Ubuntu, then you can try KVM. After installing, use the KVM module to install and run multiple virtual machines (guest) on Linux servers.

These virtual machines can be managed via the virt-manager graphical user interface or virt-install & virsh CLI commands.

Check your System

Not all systems can install and run KVM modules. If you’re running a server that isn’t compatible, KVM can’t be used on it. to check, run the commands below to install a CPU checker tool:

sudo apt install cpu-checker
sudo kvm-ok

After installing, the above commands check the CPU compatibility with KVM. If KVM is compatible you should get the message that KVM acceleration can be used.

KVM acceleration can be used

if KVM isn’t compatible with your system, you’ll get a message that reads

INFO: Your CPU does not support KVM extensions
KVM acceleration can NOT be used

The message above shows you can’t run KVM.

Install KVM Packages

If step 1 is good, then run the commands below to install KVM packages to enable full virtualization functionality on Ubuntu via the Linux kernel.

sudo update
sudo apt install qemu qemu-kvm libvirt-bin  bridge-utils  virt-manager

After installing the KVM packages, run the commands below to start and enable it to automatically startup when the system boots.

sudo systemctl start libvirtd
sudo systemctl enable libvirtd

Configure Network Bridge for the Virtual Machine

KVM virtualization module requires a network bridge for its virtual guest machines. On Ubuntu 18.04 server, a new file /etc/netplan/50-cloud-init.yaml file is created for network configurations. Use this file to configure static IP, and bridge and netplan utility will refer to this file.

To create a new network bridge, run the commands below to open the Ubuntu network config file.

sudo nano /etc/netplan/50-cloud-init.yaml

Then add a new bridge section [highlighted] to the file and save.

network:
  ethernets:
    enp0s3:
      dhcp4: no
      dhcp6: no
  version 2

  bridges:
    br0:
      interfaces: [enp0s3]
      dhcp4: no
      dhcp6: no
      addresses: [172.168.0.10/24]
      gateway4: 172.168.0.1
      nameservers:
        addresses: [172.168.0.1]

Save the file and exit

Next, run the commands below to apply the changes.

sudo netplan apply
sudo netplan --debug  apply

Next, continue below to start creating your VMs.

Create New VMs

Now that the server is configured, open the KVM virtual machine manager and start creating a new virtual guest machine. First, connect to the server, then create a new machine by clicking New Virtual Machine

Then choose how to install the guest machine. you can use local ISO media or via network / PXE install

Next, browse for the ISO file if you’re going to be installing via ISO and select the file with the OS. In this post, we’re going to be installing the Ubuntu server.